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The Sea of Monsters · Garden Heights
Part 4
for The Sea of Monsters · Part 4 · Chapters 9–10
8 Parts40 min
What Happens in Part 4
Part 4 names the enemy and puts the story on the water for good. The stowaways are caught aboard the Princess Andromeda and brought to Luke Castellan, who is in no hurry at all. He admits that he poisoned Thalia’s tree himself — the crime the camp had pinned on Chiron — and makes it clear the Golden Fleece is meant for something far larger than one dying pine. With the exits shut and the morning already scheduled, Percy Jackson opens Hermes’ thermos all the way, and the wind takes him, Annabeth Chase, and Tyson off the ship and into open sea. What picks them up is not a rescue so much as a complication: the CSS Birmingham, a Civil War ironclad crewed by the undead and commanded by Clarisse La Rue, whose quest this officially is. Percy hands her Luke’s confession; she keeps her command. Between watches he dreams of Grover Underwood running out of stalling tactics, while the ironclad steams toward the narrow entrance to the Sea of Monsters.
What We Will Learn
Section
What you will practice
Vocabulary
Confrontation and ship words: betrayal, defiance, ironclad, salvage, wary…
Literary Elements
The antagonist who explains himself, exposition under pressure, and the chapter-end drop
Cross-Curricular
The Sargasso Sea — a sea with no shore — and why the Bermuda Triangle story refuses to die
Chapter Summary
Ch.
What happens
Ch.9
I Have the Worst Family Reunion Ever — the stowaways are caught aboard the Princess Andromeda and brought to Luke Castellan, who is delighted to see them and in no hurry. He admits what the camp only suspected: he poisoned Thalia’s tree himself, and he intends the Golden Fleece to be used on something far worse than a dying pine. Percy learns how completely he has been outmaneuvered, and how little Luke thinks of Tyson. With execution scheduled and the exits closed, Percy opens Hermes’ thermos wide, and the wind takes all three of them off the ship and into the sea.
Ch.10
We Ride the Confederate Zombies — picked out of the water, the three find themselves aboard the CSS Birmingham, a Civil War ironclad crewed by the undead and commanded, to Percy’s dismay, by Clarisse La Rue. The quest is hers, she reminds him, and she is not sharing it. Percy passes on what Luke admitted, and the news lands badly with a daughter of Ares who wanted this voyage to be hers alone. Between watches he dreams of Grover running out of excuses, while ahead of the ironclad the entrance to the Sea of Monsters waits — a gap so narrow that both sides of it are named after monsters.
Part 1
Vocabulary
Study 10 key words from Chapters 9–10, then answer each question.
🌿Knowledge Bank · The Sea Named After a Grape
Oceanography · Sargasso VocabularyThe Sargasso Sea got its name from sailors, not scientists, and the vocabulary still shows it. The floating brown weed that covers it is sargassum, from a Portuguese word for a small grape, because the round gas-filled bladders studding each frond looked like fruit drifting in rows. Those bladders are the reason the mats never sink; they make the whole plant buoyant, so the weed lives its entire life at the surface and touches bottom nowhere. A sailing ship stuck in the weak winds of that region was said to be becalmed, a word that sounds peaceful and terrified whole crews, since a ship without wind cannot reach food or fresh water. Where the mats gather thickly, sailors spoke of a windrow, a long line of weed combed into a stripe by the surface breeze. Modern researchers kept the sailors’ words and added measurements, because in oceanography a good old name still beats a new number.
betrayaln.Ch.9
The breaking of trust by someone close to you
“The betrayal stung more because it came from a friend.”
confrontv.Ch.9
To face someone directly about what they have done
“Percy had to confront the person he once looked up to.”
smugadj.Ch.9
Pleased with oneself in an irritating way
“Luke stayed smug even while the wind tore at the deck.”
dreadn.Ch.9
A heavy fear of something that is still coming
“Waiting for dawn filled the room with dread.”
defiancen.Ch.9
Open refusal to obey a person in power
“Opening the thermos was an act of pure defiance.”
ironcladn.Ch.10
A warship covered in protective iron plating
“The ironclad sat low and dark against the swell.”
hulln.Ch.10
The main body of a ship that sits in the water
“Water slapped along the iron hull all night.”
trucen.Ch.10
An agreement to stop fighting for a time
“Their truce lasted exactly as long as it had to.”
salvagev.Ch.10
To rescue something usable from loss or wreck
“They tried to salvage a plan out of a ruined night.”
waryadj.Ch.10
Watchful because trouble may be close
“Clarisse stayed wary of every word Percy said.”
ⓘ The vocabulary words in this list are selected to help you understand and complete this workbook. Some may not appear verbatim in the original novel.
1A warship protected by heavy metal plating is called an ___.Ch.10
2To be ‘wary’ of someone is to trust them completely.Ch.10
3The breaking of trust by someone close to you is a ___.Ch.9
4Fill in each blank with the correct word.Ch.9–10
Word choices:defiancetrucesmughull- some words will not be used
Opening the thermos in front of Luke was an act of .
Water knocked against the iron all night long.
5A ‘truce’ is an agreement to stop fighting for a while.Ch.10
6To face someone directly about what they have done is to ___ them.Ch.9
7‘Salvage’ means to throw away whatever has been damaged.Ch.9–10
8Fill in the blanks with the correct words.Ch.9–10
Word choices:dreadbetrayalironcladwary- some words will not be used
Waiting for the morning filled the cabin with .
Clarisse stayed of everything the newcomers told her.
9Someone who is pleased with himself in an annoying way is ___.Ch.9
10The main body of a ship, the part that sits in the water, is the ___.Ch.10
Part 2
Comprehension
Show you understood what happens in Chapters 9–10.
🌊Knowledge Bank · A Sea With Water for Shores
Oceanography · The Sargasso SeaEvery other sea on Earth is named by the land around it. The Sargasso Sea, in the western North Atlantic, has no land around it at all; its edges are moving water, warm currents that ring it and hold it in place. Inside that ring the water is famously clear, warm, salty, and slow, and it carries thick mats of floating brown weed that never anchor to the bottom. For centuries the region had a grim reputation, because sailing ships crossing it often met weak, unreliable wind and could sit for days going nowhere. The stories about weed seizing hulls were wrong, but the stillness was real enough to frighten crews. What the stillness actually produces is life. European and American eels cross thousands of miles to spawn there, so nearly every eel in the rivers of two continents begins here; young sea turtles ride the mats for years, hidden. The modern threat is that the same currents deliver drifting plastic.
1What does Luke admit to Percy aboard the Princess Andromeda?Ch.9
2Why is Luke unhurried when the stowaways are brought to him?Ch.9
3Luke intends the Golden Fleece to be used for something other than saving the camp’s tree.Ch.9
4How do Percy, Annabeth, and Tyson get off the Princess Andromeda?Ch.9
5Write the numbers 1–5 in the boxes to show the correct order of events in Chapters 9–10. Number 1 = what happens first.Ch.9–10
Percy opens the thermos and the three are blown off the ship.
A Civil War ironclad crewed by the undead picks them up.
Percy dreams of Grover while the ironclad sails on.
Luke admits that he poisoned Thalia’s tree.
The stowaways are caught and taken to Luke.
6Clarisse is glad to have Percy aboard and immediately shares command of the quest.Ch.10
7What kind of ship is the CSS Birmingham?Ch.10
8How does Clarisse react to Percy’s news about Luke?Ch.10
9Percy dreams of Grover again while he is aboard the ironclad.Ch.10
10By the end of Ch.10, where is the ironclad heading?Ch.10
Part 3
Literary Elements
Understanding HOW and WHY Rick Riordan tells the story across Chapters 9–10.
🎭Knowledge Bank · Villains Who Explain Themselves
Literary Craft · Antagonist and ExpositionA story has to get information to its reader somehow, and the least graceful way is to have a character stand still and describe the plot. Riordan uses an old solution: let the antagonist do the explaining while he thinks he is winning. Luke talks because he is certain, and certainty makes people generous with secrets. The scene therefore performs two jobs at once, delivering the poisoning of the tree and the real plan for the Fleece while the danger keeps rising, so the reader never feels lectured. Writers call this buried delivery — exposition hidden inside conflict. Riordan then closes both chapters on a drop, the technique serial storytellers have used since newspapers printed novels a piece at a time: end where the situation changes and the outcome is unknown. That is a cliffhanger, and its power comes from timing rather than from surprise. Notice how little of Part 4 is description; almost all of it is somebody pressing an advantage.
Antagonist
Luke gets a full scene rather than a silhouette: charming, patient, and completely sure he is the one being reasonable.
Exposition
The plot’s biggest secret arrives inside a threat, so the information and the danger reach the reader in the same breath.
Cliffhanger
Both chapters end by dropping the floor out — one into open water, one into a strait named for monsters.
1A character who stands directly against the hero is the story’s ___.Ch.9
2Fill in each blank with the correct literary term.Ch.9–10
Word choices:expositioncliffhangerstanzameter- some words will not be used
Background the reader needs is called .
Ending a chapter mid-danger is a .
3Why does Riordan let Luke deliver the story’s biggest secret himself?Ch.9
4Luke is written as a snarling monster with no charm at all.Ch.9
5Ending Ch.9 with the three of them blown into open water is an example of ___.Ch.9
6The undead Confederate crew works in the story mainly to ___.Ch.10
7Exposition means the part of a story where the conflict is finally resolved.Ch.9–10
8Fill in each blank with the correct literary term.Ch.9–10
Word choices:antagonistsuspensesimilerefrain- some words will not be used
The character working against the hero is the .
Waiting for dawn on a hostile ship builds .
9Riordan raises the danger and delivers plot information in the same scene.Ch.9
10Chapters 9–10 mainly work to ___.Ch.9–10
Part 4
Think Deeper
Four deeper challenges — no single-word recall. Read, weigh the evidence, and reason it out.
🔍Knowledge Bank · Why the Triangle Story Will Not Sink
Critical Thinking · Testing a LegendIn 1964 a magazine writer drew an imaginary triangle between Miami, Bermuda, and Puerto Rico, gathered a set of ship and aircraft losses inside it, and gave the collection a name. Later researchers went back to the original records, and the pattern fell apart. Some losses had happened in storms severe enough to sink anything; some had happened hundreds of miles outside the lines; several vessels reported as vanished without trace had in fact left wreckage and survivors. The area is also among the busiest in the world for shipping and flying, so a raw count of accidents there should be high with no mystery involved at all. The legend survives anyway, and the reasons are worth naming. Retellings copy earlier retellings rather than sources, dramatic cases get repeated while ordinary explanations are dropped, and readers remember the hits and forget the misses — a habit psychologists call confirmation bias. Testing a claim like this takes only one unglamorous step: go back to the original record.
Think back over these chapters. A boy is walked down a corridor of a ship that has too many decks and not one guest, into a room where the person waiting is delighted to see him. The confession comes easily, because certainty makes people talkative, and every answer is worse than the question. Then a lid comes off a thermos all the way, and the sea takes over. Later there is iron underfoot instead of carpet, a crew that stopped aging a hundred and fifty years ago, and a girl in the wheelhouse who will not share one inch of her quest. Ahead, the water narrows toward a gap with a monster named on either side.
Original passage written for Garden Heights — not a quotation from the novel.
1Claim: “Part 4 replaces the camp’s guesses with information that can be checked.” — choose the two details that best prove it.Claim & Evidence
2Checked against the record, or Repeated because it is a good story? Tap each detail to send it left or right.Sort into two
◄ Checked against the recordRepeated because it is a good story ►
3Match each cause to its result. For each cause, pick its result.Cause & Effect
Luke is certain the exits are already closed→
Percy opens Hermes’ thermos all the way→
An ironclad crewed by the dead pulls them aboard→
Percy repeats Luke’s confession to Clarisse→
4Fill both blanks to complete the reasoning.Build the Argument
The Bermuda Triangle keeps its reputation even after investigation because , which shows that .
Part 5
Standardized Test
Reading passage · The Sea That Has No Shore · Central Ideas & Words in Context · SAT & TOEFL-style practice
🎯 What this section practices
You already have these skills from the sections above — here they appear in the exact question types the SAT and TOEFL use. Read the passage (the highlighted words are tested below), then answer. Tap an answer to select it, then tap it again to confirm — you can change your choice until you confirm.
SATCentral Ideas — the main point of the passage as a whole
TOEFLFactual Information×3 — a fact stated directly in the passage
SATWords in Context×2 — what a word means the way this passage uses it
TOEFLInsert Text — where a given sentence best fits among four marked spots
TOEFLVocabulary — the meaning of a tested word as this passage uses it
SATInference — a conclusion the passage supports without ever stating it outright
SATAuthor’s Purpose — what the author is trying to accomplish by writing this
Every other sea is defined by the land that holds it. The Sargasso Sea, in the western North Atlantic, is defined by moving water instead, ringed by warm currents rather than by any coast. Inside that ring the water is clear, warm, and slow, carrying thick mats of floating brown seaweed that never touch the bottom. The weed stays up because thousands of small gas-filled bladders make each frond buoyant. Ships that wandered in often met weak wind and sat for days becalmed among the mats, which earned the region its reputation as a trap.
Biologists later found a nursery rather than a graveyard. European and American eels spend years in rivers, then swim thousands of miles to spawn in the Sargasso, so nearly every eel on two continents begins life in this one patch of ocean. Young sea turtles drift in the weed for years, hidden from most predators. Crabs, shrimp, and small fish live nowhere else, colored and shaped to disappear against the fronds. The sea’s problem now is not stillness but delivery: the same currents that hold the weed in place also gather drifting plastic and concentrate it where the animals feed.
Part of the same stretch of ocean is better known by another name. In 1964 a magazine writer collected ship and aircraft losses inside an imagined triangle between Miami, Bermuda, and Puerto Rico, and the label stuck. Investigators who checked the original records found ordinary causes: storms, overloaded aircraft, mistaken positions, and losses that happened well outside the lines. The region is among the world’s busiest for shipping and flying, so a plain count of accidents should be high without any anomaly at all. The legend survives because a story promising mystery is retold far more often than the dull report that explains it.
Original passage written for Garden Heights — not a quotation from the novel.
1What is the main idea of the passage?SAT · Central Ideas
2According to the passage, what forms the boundaries of the Sargasso Sea?TOEFL · Factual Information
3In the passage, buoyant means ___.SAT · Words in Context
4According to the passage, why do eels matter to this sea?TOEFL · Factual Information
5Insert Text (TOEFL). Look at the four squares [1]–[4] in the excerpt below. They show where this sentence could be added: “Neither guess was right, though both stayed in print for decades.”
The sea takes its name from a Portuguese word for a small grape. [1] Sailors chose that name because the round bladders studding the weed looked like fruit floating in rows. [2] For a long time crews assumed the bladders were seeds, and that the mats had been torn loose from some distant shore and left to rot. [3] Survey ships in the nineteenth century finally settled the matter, and the weed turned out to be a permanently floating species with a resident community of its own. [4]
Where would the sentence fit best?TOEFL · Insert Text
6In the passage, becalmed means ___.TOEFL · Vocabulary
7According to the passage, what did investigators find in the original loss records?TOEFL · Factual Information
8In the passage, anomaly means ___.SAT · Words in Context
9The passage suggests that the Sargasso’s stillness is best described as ___.SAT · Inference
10Why does the author end with the point about retelling?SAT · Author’s Purpose
Part 6 · Optional
Creative Writing
A bonus challenge to practice your English. Take your time and have fun with it.
About This Section
This writing task is optional and is not part of your auto-graded score. The feedback below checks only the basics — length, spelling, and grammar — not whether your ideas are right or wrong. It is meant for classroom discussion and creative practice, so feel free to use your imagination!
Writing Task — Part 4 “The Story That Would Not Sink”
A legend about vanishing ships survived every check of the records, because a good story travels faster than a correction. Write about something you believed — a rumor, a warning, a fact everyone repeated — that turned out to be wrong. How did you find out, and what made the story so easy to believe in the first place? 6–10 sentences.
You can start with: “Everybody said it, so I never thought to check...”
0 / 40 words minimum
🗣 Teach It · Just for Fun (optional)
No right or wrong — close the screen and tell someone nearby what happened in this part. Can’t find anyone? Tell yourself out loud. The moment you teach it, you truly understand it.
Part 4 Complete!
You finished Chapters 9–10 of The Sea of Monsters.
Here are your auto-graded results:
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points out of 100
Your Writing
Your writing was checked automatically for length, spelling, grammar, and whether you included the key parts of the scene. Scroll back to Part 5 anytime to read your feedback and improve your work.
Independent study guide by Garden Heights. Not affiliated with or endorsed by Rick Riordan. Contains original analysis only; no text from the novel is reproduced. Reference text: This workbook follows Rick Riordan’s classic text (the standard Puffin edition sold worldwide). Revised 2023 UK editions change some wording and may not match the vocabulary studied here.
