On their first full day adrift, Maralyn establishes a routine, beginning with breakfast. Maurice worries that their rations are meager. Maralyn reveals she salvaged the Hiscock book and a biography of Richard III for mental stimulation. Maurice recognizes that staying busy prevents dangerous thoughts.

Maralyn inventories their possessions and remaining food: 33 food tins, dates, nuts, and a Dundee cake for her April 24 birthday. She establishes a one-pint daily water ration for each of them and creates a meal timetable, estimating that supplies will last 20 days. Maurice uses his compass and chart to estimate that they are 250 miles north of Ecuador and 300 miles east of the Galápagos. The currents make reaching the islands unlikely. He proposes rowing the dinghy south 10 miles per day but defers the decision to Maralyn. She immediately agrees to row at night in two-hour shifts, and Maurice realizes his captaincy had ended.

They eat their first dinner and agree to wait one day before starting to row. Their first night is uncomfortable; they take turns sleeping, feeling every wave through the thin floor of the raft.

They wake to intense thirst. Maurice discovers that four gallons of water have been contaminated by seawater. The oppressive heat forces them to shelter with wet clothes against their skin.

On their second night, they begin rowing south, with Maurice navigating by compass and stars. Towing the raft severely limits their progress. They row eight hours in shifts. To combat dehydration, Maralyn doubles their water ration.

In the morning, Maurice calculates that they rowed only four miles south while drifting thirty miles west. Maralyn sees distant clouds and declares they must be over the Galápagos. After three more nights of rowing, Maurice confirms that they gained only 10 miles south. He suggests stopping rowing to conserve energy and water. 

Maralyn rigs a makeshift sail in the dinghy, using oars and a sail bag. Maurice warns that it will drive them northwest. Maralyn counters that it will push them toward a shipping lane and the American coast. Maurice knows the trade winds will likely push them southwest but finds her impossible to discourage.

A violent thunderstorm passes with no rain. That night, sharks circle, and a turtle tangles in the dinghy ropes.

On March 12, Maralyn spots a ship about a mile away. Maurice tries three of their flares, but all are duds, producing no light or smoke. His torch signal is futile. They watch helplessly as the ship disappears.

Maralyn rationalizes that the crew must have been below deck during the early morning, explaining why they were not seen. She writes in her diary that they feel tricked but expresses faith that they will be third time lucky.

Their location is a convergence of five ocean currents near the Galápagos, creating a marine-life hub. Turtles bash themselves against the raft’s underside, and Maurice worries that their shells could puncture it.

With gas exhausted and food dwindling, Maralyn suggests killing a turtle. They haul one into the dinghy. Maurice knocks it unconscious, and Maralyn attempts decapitation with inadequate tools. The turtle revives and struggles before she severs an artery. They collect the blood but cannot drink it. They butcher the turtle, eating the raw meat.

The blood attracts fish. Maurice discovers that their fishhooks are missing. Maralyn improvises a hook from a safety pin and successfully catches a fish. They process it completely, drinking liquid from the eyes and eating liver, roe, and fillets raw. Fishing becomes a daily routine. A second turtle fights fiercely, biting Maurice’s ankle before they kill it.

Maralyn attempts to harness turtles to pull the raft, but when the second swims opposite the first, the plan fails. They keep one small turtle as a pet.

They mark time through their pet turtle’s habits and Maralyn’s diary. She draws a calendar on the canopy. Maurice uses his watch, occasionally resetting it by the sun. Maralyn daydreams of the English countryside and imagines camping in the Lake District. Maurice makes a signal flag from orange oilskins.

On March 14, a whale surfaces 20 feet away. Maurice remains calm as the whale’s blowhole sprays them. After several peaceful minutes, it dives cleanly away. Maralyn regrets not photographing it, assuming they will survive. Maurice marvels at her unshakable belief.

The weather cools, and the wind strengthens, spraying water into the raft. The sea anchor breaks, and Maurice replaces it with oilskins. The connecting rope tangles, making the raft spin. Constant dampness causes painful sores.

On March 24, it finally rains. They collect water from the ventilation ducts, discarding the first rubber-tasting batch. After two days of storms, they have replaced their water supply.

On March 26, Maurice keeps watch and resolves to become more patient and less egotistical.

After three weeks adrift, they are severely emaciated. They eat the last of the Dundee cake and reduce their daily food to half rations.

Maralyn asks Maurice how she looks. She has not menstruated since the sinking. Maurice sees her gaunt, aged face and painfully thin body. He feels asexual, focused only on survival. He tells her honestly that she looks gaunt.

Their rotting, salt-encrusted clothes cause painful chafing. Their soap disintegrates in saltwater. Maralyn trims Maurice’s mustache and spends 15 minutes daily untangling her hair, resisting the urge to cut it off, as it would symbolize surrender.

On March 29, Maralyn spots a second ship. Maurice tries their last two flares; the first is a dud, but the second ignites and briefly illuminates the scene. The ship continues on.

On April 10, they spot a third ship and wave their oilskins, but it motors past. Two days later, a fourth ship appears, and they use a homemade smoke signal that causes the vessel to turn toward them, only to pause and then sail away. Maralyn is devastated but declares it was not the ship meant to rescue them, predicting that a large black Russian container ship would save them.

Their philosophies diverge: Maralyn believes in fate and determination; Maurice sees only random chance. To him, dying by suicide is their only definitive choice.

A fifth ship appears at night. Their homemade flare will not light in the wind, and their torch battery is dead. Maralyn feels now that the ships disturb their peace rather than offer hope. They discover their kerosene is contaminated, and the matches are too damp; when dried, the match heads crumble, leaving them with no way to signal for help.