Synthetic narcotic neurotoxin baca is becoming real

In a partially flooded future Miami, climate change has forced most of the population to work at night. Recent war veterans Nick Bannister and Emily "Watts" Sanders operate a machine that allows clients to relive memories. One morning, a walk-in client, Mae, asks for their help finding her missing keys. On observing her memories of the night, Nick learns she is a nightclub singer, and feels a connection with her when she sings his favorite song, "Where or When". He begins a relationship with her, and when she disappears after a few months, he uses the machine repeatedly to relive memories of his times with her. Watts confronts him about this, but she also has a close attachment to Nick, an alcohol addiction, and an estranged daughter. Nick and Watts use the same technology to help the state prosecution retrieve memories from suspects. In one such case, they discover that Mae was mistress to a New Orleans drug kingpin named Saint Joe, who addicted her to a narcotic called baca. These memories also reveal that a corrupt cop, Cyrus Boothe, worked for Joe, and that Mae stole a stash of Joe's baca before fleeing New Orleans for Miami. Nick goes to New Orleans to confront Joe, who has no news of Mae. He tells his men to drown Nick, but Watts rescues him, killing Joe. Nick and Watts then use their memory machine to discover that Mae broke into the vault where they store clients' memories, and stole recordings of the memories of Elsa Carine, a client who relived trysts with Walter Sylvan, an older wealthy "land baron" who has recently died. Nick's investigations reveal that Elsa had a son with Walter, but she was recently murdered by Boothe, and her son, Freddie, was kidnapped by Mae. After a confrontation, Walter's widow points Nick towards their location, where he and Boothe fight. Boothe almost drowns, but Nick rescues him and drugs him, then takes him back to his memory machine. Boothe's memories reveal how he pressured Mae to seduce Nick and steal Elsa's memories: she researched Nick's background, and the lost keys were staged. Then they reveal how she came to love Nick, and how she took Freddie and fled to protect him from Boothe. Later, Boothe finds Mae and tries to force her to reveal Freddie's location. As Nick watches the memory of a speech Mae delivers to Boothe, he realises it is meant for him: she confesses her love for him, reveals the location of Freddie, then takes an overdose of baca and falls off a platform to her death. Nick avenges her death by forcing Boothe to relive his worst memory of being burned by Joe's men. He also confronts Walter's legitimate son Sebastian, who hired Boothe to protect his inheritance. He then confesses to Watts that he intentionally "burned" Boothe's memories, a major crime. He is convicted, but is allowed to serve his sentence using his machine to relive his time with Mae thereafter. An older Watts reunites with her family, and watches Nick reliving a memory with Mae, in which he recounts a shortened version of the story of Orpheus and Eurydice, ending with the lovers reunited on their way out of Hades, but before the usual sad end of the story.