On the desolate streets of Miami, Florida, in a future overwhelmed by rising waters due to climate change, society has become fragmented and impoverished. The once lively cityscape has been flooded, leaving many residents living on boats or in makeshift slum areas, struggling to survive amid chaos and despair. In this grim environment, Nicholas “Nick” Bannister, a former military veteran, has established a business offering a unique escape—through a device called a reminiscence machine, which allows clients to relive their cherished memories. Nick operates this service alongside his trusted partner, Emily “Watts” Sanders, also a veteran, providing a glimpse of hope and nostalgia in a broken world.
Nick's story takes a turn when he is approached by the police to investigate Walter Sylvan, a powerful and corrupt land baron notorious for monopolizing the region’s remaining dry land. Despite dismissing earlier police calls due to delays, Nick overhears Walter's son, Sebastian, asking about “her,” hinting at a mysterious woman involved in his affairs. One evening, a striking woman named Mae, played by Rebecca Ferguson, enters Nick’s office seeking help to find her lost keys. Enthralled by her allure and a song she sings—one that reminds Nick of his grandfather—he soon becomes captivated by Mae’s charm. Their relationship blossoms as she shares stories of her travels and the mysterious off-shore seahouse where she once drifted ashore.
As months pass, Mae mysteriously disappears. Nick, obsessed with discovering her whereabouts, begins a relentless investigation, revisiting memories and following clues that lead him into murky worlds involving underworld figures like Saint Joe, a crime lord played by Daniel Wu. Through snippets of past encounters, including Mae's appearance with Joe and a crooked cop, Nick uncovers her involvement in thefts and drug dealings, raising questions about her true intentions. Driven to find answers, Nick travels to New Orleans to confront Saint Joe himself, risking his life through daring disguises and intense gunfights.
The truth begins to unravel: Mae had betrayed Nick, stealing his memories—specifically, recordings of Elsa, a woman from Nick’s past. She was also connected to a conspiracy involving Walter Sylvan’s illegitimate child, Elsa’s son, Freddie, who was kidnapped and presumed dead. As Nick digs deeper, he faces the shocking reality that Mae was working with Cyrus, a ruthless enforcer who had blackmailed her. Cyrus, scarred and dangerous, confesses that he and Mae were once partners serving Saint Joe but that Mae chose to go straight, trying to start anew. She later rescued Freddie and tried to escape Cyrus’s grip, but he captured and drugged her, forcing her into a deadly game of deception and betrayal.
In a heartbreaking climax, Mae sacrifices herself, leaving an indirect message that reveals her genuine love for Nick and her regret for hiding the truth. Nick, overwhelmed with grief, chooses to permanently incapacitate Cyrus rather than kill him, using the rememiscence machine to subject Cyrus to a painful lobotomy. In the midst of these revelations, a significant twist arises when Sebastian, Walter Sylvan’s son, is uncovered as the mastermind behind the murders of Elsa and Freddie, fearing that Freddie's existence threatened his inheritance. Nick’s relentless pursuit uncovers that Freddie is still alive, rescued by police, and safe at the seashore.
Ultimately, Nick visits Watts, now working for the police, and they reconcile amid chaos and riots. Nick’s actions to dismantle Sylvan’s monopoly—albeit morally ambiguous—lead to societal change, breaking the land monopoly and restoring some order. As the narrative closes, Nick, nearly aged, retreats into memories with Mae, reliving their love story through a hazy, nostalgic lens. His final moments are marked by a tender remembrance of telling Mae the story of Orpheus and Eurydice, symbolizing their longing for an impossible yet eternal union. Through these preserved memories, Nick finds peace, content to hold onto love and the hope of a happier ending in a world forever changed.
