Megan Lally’s What We Did to Survive (2026) is a young-adult thriller that transforms a picture-perfect spring-break vacation into a harrowing fight for survival. The novel follows high-school senior Hannah, who joins her best friend Emmy’s family for a trip to a luxury resort in Puerto Vallarta, Mexico. When Emmy’s wealthy new vacation boyfriend charters a private sailboat for their last day, Hannah and Emmy’s brother, Jackson, are brought along, but a brewing storm and a series of disastrous choices leave the teenagers stranded at sea. The story explores themes including The Dangers of Misplaced Trust, The Moral Ambiguity of Survival, and The Corrosive Power of Unchecked Privilege.

Lally is the New York Times and USA Today best-selling author of other dark, twisty young-adult thrillers, including That’s Not My Name and No Place Left to Hide. Her interest in true crime, unsolved mysteries, and high-stakes suspense shapes the survival-thriller elements of her novels. What We Did to Survive was inspired by a real trip that Lally took to Puerto Vallarta, during which a friend’s reckless decisions sparked the initial idea for the plot. The novel was named a Junior Library Guild Gold Standard Selection.

This guide refers to the 2026 Sourcebooks Fire edition.

Content Warning: The source material and guide feature depictions of illness, death, graphic violence, physical abuse, substance use, and cursing.

Plot Summary

Hannah, a senior in high school and aspiring trauma nurse, is spending spring break in Puerto Vallarta, Mexico, with her best friend, Emelia “Emmy” Cole, and Emmy’s family. The trip is a final hurrah before Hannah heads to Linfield University’s nursing program and Emmy departs on a solo world tour starting in Italy. Emmy’s older brother, Jackson Cole, a college sophomore, is also along. Hannah has harbored a secret crush on Jackson for a decade, and they kissed the previous Christmas Eve, but Jackson broke things off after his father caught him sneaking out and reminded him that he was older, away at college, and shouldn’t take advantage of Hannah’s crush. Hannah has told no one.

On the beach, a charming, wealthy boy named Bennett “Ben” Mulholland briefly flirts with Hannah before shifting his attention to Emmy. Over the next two days, Ben treats the group to excursions and pays for everything. When Emmy grows anxious about the trip ending, Ben proposes chartering a private sailboat for their last full day. Emmy’s parents agree on one condition: Jackson must chaperone.

On the morning of departure, storm clouds mass on the horizon, and the tour charters are canceled. Ben reveals that he hired Captain Keith, who lives aboard his roughly 50-foot sailboat, the Be-Yacht-Ch, after official companies refused to go out. Keith promises to return by three o’clock that afternoon. Jackson objects, but Emmy boards, and the group sets off. Keith remarks that many towns along the coast are accessible only by boat and warns that becoming stranded there would be like washing up on a deserted island. During conversation, Ben belittles Hannah’s nursing ambitions and mocks her father’s career as a pediatric nurse practitioner, and when Hannah objects to Ben inviting himself on Emmy’s world tour, both Ben and Emmy dismiss her concerns.

After hours of sailing, lightning strikes close by. The storm is no longer on the horizon but directly overhead, and the boat has drifted toward open ocean. The group finds Keith passed out drunk below deck, having consumed most of Ben’s tequila. A violent confrontation erupts: Ben breaks Keith’s nose with a knee strike. Hannah tends to the injury, drawing on her lifeguard training and knowledge gained from her father’s medical career. Keith warns her that Ben smiled while hurting him. When Keith announces that he’ll press assault charges, Ben deliberately releases the boat’s wheel. The boom swings violently, striking Keith in the head and sending him overboard. Hannah dives in after him, but the current is too strong, and visibility is zero. Keith doesn’t resurface.

Ben insists that the wheel slipped and threatens to frame all three teenagers as complicit. Hannah tells him that she saw him let go on purpose, and Jackson privately confirms that he believes her. The storm forces everyone below deck, where they discover that the radio has no power and that their phones have no service. Overnight, Jackson catches Ben cutting through the boat’s navigation wires with a folding knife. Ben admits that he destroyed the radio to prevent them from calling for help and to keep them silent about Keith’s death. Hannah confiscates the knife and locks Ben in the bathroom by threading a mesh produce bag through the door handles and tying it tight.

At dawn, the mast has snapped, the motor won’t start, and the cabin is flooded. Hannah rigs a siphon from a spare hose to drain the water and inventories their meager supplies: a few cans of food, some bread, fruit snacks, peanut butter, and very limited drinking water. Jackson confesses that he regretted ending things at Christmas and has been unable to stop thinking about her. They kiss, and Emmy walks in, furious at being kept in the dark.

Then, Ben escapes the bathroom by setting a fire with a gold lighter that Hannah forgot to confiscate. He grabs Hannah and locks his forearm around her throat. She elbows him free, and Jackson punches Ben off the boat, refusing to let him back aboard until he promises full cooperation. Ben, terrified by a pod of dolphins that he mistakes for sharks, agrees. Emmy privately reveals that her apparent loyalty to Ben has been an act: She has been pretending to side with him to gather information.

The second storm arrives with even larger waves. Ben tries to rip Hannah’s life vest from her, and Emmy slams his head into the cabin wall. A massive wave crashes toward them. Jackson shoves Emmy through the hatch to safety and tries to push Hannah in, but it’s too late.

Hannah regains consciousness floating in the water, tied to the boat by a rope she doesn’t remember securing. The Be-Yacht-Ch lies on its side, three-quarters submerged. Its keel is missing, leaving only rusted supports behind. She hears three knocks from inside the hull and finds Emmy trapped in an air pocket, her forearm gashed to the bone and badly infected. Hannah dives through the submerged hatch and drags Emmy out, along with a bag of remaining supplies that Emmy kept strapped to her body.

Hannah then spots Jackson clinging to the emergency flotation ring in the water. He appears sunburned but functional, and he refuses food and water, directing everything to Emmy. After Emmy has a seizure, Hannah retrieves an emergency raft from the sinking cabin and inflates it. She and Jackson propel it toward a thin line of green on the horizon. After hours in the water, they collapse on a beach backed by dense jungle.

On the shore, Hannah finds fresh water, tends Emmy’s fever, builds a signal fire, and carves “HELP” in the sand. She hallucinates a rescue helicopter that vanishes, shaking her confidence in her own perceptions. Their remaining food disappears overnight, and Hannah spots an intruder emerging from the jungle after he sabotages the camp. While tracking him the next day, she discovers a hidden shelter containing her stolen supplies and a shirt she recognizes as Ben’s.

Ben confronts her, battered but alive. A flotation ring kept him alive, and he washed ashore separately. When he discovered that Hannah and Emmy had also survived, he began sabotaging their camp to eliminate the witnesses to Keith’s murder. Then, he reveals what happened during the second storm: Jackson found Ben tangled in the safety cables and used Ben’s knife to cut a line and tie it around the unconscious Hannah, telling Ben, “You’re not going to make it, but she will” (261). Before the next wave hit, Ben stabbed Jackson in the neck.

Hannah realizes that Jackson never carried Emmy, never ate or drank, and never left footprints on the beach. He only spoke to her, always saying what she needed to hear to keep going. She realizes that Jackson died during the second storm and that her interactions with him onshore were hallucinations.

Ben attacks, chasing Hannah to a stone outcropping above jagged rocks and dragging her toward the edge. He confirms that he plans to kill Emmy too. Hannah tangles her legs around his ankles and pulls. Ben falls backward off the cliff onto the rocks below. A helicopter approaches after seeing her signal fire and lands on the beach. Hannah returns to Emmy and tells her that they’re going home.

In the Epilogue, set almost a year later, Hannah is a nursing student at Linfield, struggling with grief. Emmy has recovered from her injuries and departed on her world tour. Ben’s body was never found, and public opinion cast him as the villain. Emmy surprises Hannah at college and proposes that they spend spring break in Italy, the destination she originally skipped because Ben had tainted it. Hannah agrees, with one condition: no boats. They press their frayed friendship bracelets together, and the novel ends with Hannah and Emmy beginning to move forward with their lives.