The Castaways

The novel alternates between two timelines, "Then" and "Now," unraveling the mystery of a small plane that vanished over the South Pacific. In the present-day chapters, Erin Holme, a London journalist, is consumed by the disappearance of her older sister, Lori Holme, who was a passenger on flight FJ209 two years earlier. The plane, carrying two crew and seven passengers from Nadi airport in Fiji to the remote island of Limaji, vanished from radar without a trace. Erin has spent the intervening years obsessively investigating, papering a spare room in her flat with clippings, maps, and photos. She was supposed to be on the flight herself but missed it after a devastating argument with Lori the night before.

The "Then" chapters reconstruct events leading up to and following the crash. Lori, an artist reeling from her ex-husband Pete's affair and their failed IVF attempts, had impulsively booked the Fiji trip for herself and Erin. Over dinner at their hotel, the conversation turns toxic: Erin reveals she once caught Pete with another woman years earlier and kept it secret. Lori accuses Erin of breaking their lifelong promise to always tell each other everything, a vow made after losing both parents young. Erin storms out and ends up in a bar, where she meets Captain Mike Brass, the pilot scheduled to fly their plane the next morning. It is the anniversary of his daughter Natasha's death from a drug overdose, and Mike, who has an alcohol addiction and has been sober for three years, is testing himself with a glass of whisky. Erin tells him to drink up, and they spend the evening getting heavily drunk together. At closing time, Mike kisses her; she pushes him away and flees, sleeping on a beach. She misses the morning flight. Lori boards alone.

At the gate, Lori observes her fellow passengers: Daniel Eldridge, a property developer speaking nervously on his phone; Felix Tyler, a young man who destroys his SIM card and discards his phone; an elderly American couple, Jack and Ruth Bantock; and a young mother named Holly Senton with her newborn son, Sonny. The flight departs into worsening weather. Turbulence escalates, and the air stewardess, Kaali Halle, announces a fuel problem requiring an emergency landing. The plane plummets.

Lori regains consciousness in the smoking wreckage. Jack, Ruth, Holly, and Kaali are dead. Five people survive: Lori, Felix, Daniel, Mike, and baby Sonny. They emerge onto the beach of an unnamed, uninhabited island far off the planned flight path, meaning rescue teams will be searching hundreds of miles of open ocean. The group establishes a jungle camp near the wreck. Felix finds fresh water and fruit. Mike stations himself on a ridge top with binoculars to watch for boats. Daniel builds signal fires. Lori takes sole responsibility for Sonny, rationing his dwindling formula, which gives them roughly four weeks before it runs out.

In the present, Erin's investigation is upended when a newspaper announces that Mike Brass has been found alive in Fiji under a false identity. A police transcript reveals he has a brain tumor and claims to be the sole survivor. Erin flies to Fiji and talks her way into the hospice where Mike is dying. He confirms Lori is dead and says the survivors put the bodies in the sea, adding, "We had no choice" (64). The pronoun "we" contradicts his claim of being the only survivor. Mike's son, Nathan Brass, forces Erin from the room before she can press further. Despite initial hostility, Nathan later reveals that he too believes his father is hiding something, and the two form an uneasy alliance.

On the island, the "Then" timeline traces the survivors' deterioration over 33 days. Daniel grows aggressive, kissing Lori without her consent and watching her from the shadows. Lori and Felix develop a secret romance. The group's dive knife goes missing, heightening paranoia. On the ridge top, Mike snaps and chokes Daniel near the cliff edge; Lori defuses the crisis by humming a lullaby. Lori discovers Erin's mobile phone in Mike's flight bag and begins recording video messages for her sister, treating them as an emotional lifeline.

Felix is then killed by a tiger shark while spearfishing. His death devastates Lori and leaves her alone with two men she does not trust. She suspects the missing knife, which could have helped Felix defend himself, was taken deliberately.

In the present, Mike dies before Erin can question him again. She quits her job and, in a moment of despair, climbs onto her hotel balcony railing before pulling herself back. She traces Mike's final years to a remote resort, where she finds a hand-drawn map marking the island's location. Nathan shares his father's dying words: Mike mentioned a ridge top, Lori's name, and the phrase "It wasn't an accident" (248). Erin keeps the map secret and charters a fishing boat to the island alone.

There, Erin finds the vine-covered plane wreck and the remains of the camp. She recovers her old phone and charges it, revealing Lori's video recordings. They document the crash, Sonny's care, Felix's death, and Lori's growing terror. In the final recording, Lori reveals she discovered photos and a note proving Daniel is Sonny's biological father. Erin also finds a tally tree carved with the names of the dead, including Daniel, Lori, and Sonny.

The "Then" timeline reveals the climax. On day 33, Lori confronts Daniel with proof of his paternity. He dismisses Sonny entirely and demands her silence. When she refuses, he pins her down on the beach while Sonny chokes on driftwood nearby. Understanding Daniel intends to assault her, Lori grabs a rock and strikes him in the head. She clears the driftwood from Sonny's throat, then drags Daniel's body into the sea. When he revives and grabs at her, she holds him under until he drowns. Mike appears, revealing he watched everything and has had the dive knife all along, meaning his actions indirectly caused Felix's death. He also admits the crash resulted from his own pilot error, not a mechanical fault. He proposes a pact: He will carve Lori's and Sonny's names on the tally tree so that everyone appears dead, and both he and Lori will disappear into new lives, free from accountability. A rescue boat arrives, sent by a fishing boy who visited the island days earlier. Mike bribes the boatmen, and they leave.

Erin takes her evidence to the Fijian police, believing Lori is dead. That night on the hotel beach, a figure approaches with a familiar gait. Lori speaks her name. The sisters embrace, weeping. Lori explains she has been living in Fiji's interior with Sonny, selling paintings to survive and following Erin on social media through a fake account. Erin's shock hardens into fury: Lori chose Sonny over her, abandoning their promise and allowing other passengers' families to grieve without answers for two years. Lori acknowledges the choice was hers, driven not by Mike's coercion but by her refusal to lose Sonny and her fear of prison. Erin stares at the sleeping toddler in his buggy and understands that the one thing that mattered more to Lori than being a sister was being a mother.

In an epilogue set four weeks later, Lori lives quietly with Sonny in Fiji while the police investigation continues. Erin has packed up her London flat, dismantled her investigation wall, and booked a flight to Perth, where Nathan has offered to let her stay as she begins a new life. Her final message to Lori reads, "I need to find my own island" (387), signaling that she is choosing her own path forward while leaving the door between them open.