John Mercer attends the funeral of his colleague Andrew Dyson, suffers a severe panic attack triggered by memories of past cases, hallucinates several notorious criminals in the chapel, and ultimately leaves the service escorted by his wife Eileen and his colleague Pete.
Kevin Simpson discovers a demonic entity hiding in his attic that has been monitoring him; the entity descends, binding Kevin in a hot bathtub where a masked intruder confronts him with a hammer, keys, and lighter fluid.
The devil confirms Simpson’s death, secures the eight‑minute audio recording, and prepares to leave, planning to use the tape for a phone call.
Mark Nelson arrives late on his first day as a detective under John Mercer, signs in at reception, receives a police identification photograph, is shown a chaotic office space, receives a phone call from Eileen Mercer asking him to pass a “Don’t forget” message to her husband, and is then dispatched by Pete Dwyer to a suburban homicide scene to start door‑to‑door canvassing.
Eileen Mercer is visited unexpectedly by her client James Reardon, who apologizes and mentions his daughter Karli before fleeing the scene; Eileen is left outside in the rain, unsettled by his abrupt departure.
Mark Nelson starts his first day under John Mercer, arriving at a suburban homicide where the victim is identified as Kevin James Simpson, found burned and bound in a bathtub. The team discovers a mysterious spider‑web drawing on a wall. Mercer assigns Mark to door‑to‑door canvassing and relays his wife Eileen’s “Don’t forget” reminder.
Jodie executes her routine sandwich run, grapples with a strained relationship with Scott, discovers an abandoned crying baby on a desolate waste ground, and is suddenly assaulted by a masked aggressor wielding a spray bottle.
Mark joins his team for his first homicide assignment, canvasses Kevin Simpson’s street and gathers witness descriptions of a white van and a young woman leaving the victim’s house; the detectives then listen to harrowing audio recordings of Simpson’s torture, prompting Mercer to assign CCTV review, forensic analysis, a press briefing and to open case file A6267.
Scott continues his “500 Reasons” list for Jodie, struggles with creative block and marital tension, records reason 274 after a supportive text, and intersperses his day with an iterative self‑portrait painting series and a strenuous weight‑training session.
Jodie’s lunchtime sandwich run ends with the discovery of an abandoned crying baby on a desolate waste ground and a sudden masked assault using a spray bottle; Scott continues his “500 Reasons” list, coping with creative block and marital tension, records reason 274 after a supportive text, and intersperses his day with a self‑portrait painting series and an intense weight‑training session.
Jodie and Scott, still handcuffed, trek through a slick, leaf‑covered forest while a devil‑masked captor watches; Scott slips and falls, Jodie assists him, and they press onward guided by an internal voice that urges one‑step‑at‑a‑time survival.
Mark struggles with the overwhelming 50/50 case file, receives a terse text from his parents, and discovers two sets of prints at Kevin Simpson’s house—one unknown, possibly “Jodie.” Greg reports six white‑van CCTV stills taken near the house, prompting Mercer to redirect the door‑to‑door team to investigate the vans and to demand full video/audio. Mercer and Mark review detailed CCTV footage of Detective Andrew Dyson’s murder, learning the killer used two thin‑bladed knives, fabricated the “Frank Walker” identity, and left the scene cleanly. Mercer's fatigue surfaces, and he offers Mark a short break while covering the fort.
Eileen’s anxious phone conversation with John about his late‑night work, followed by Detective Sergeant Geoff Hunter’s unexpected arrival and recorded interview of Eileen regarding her counselling of James Reardon; the interview reveals Reardon’s recent visit, his confession about assaulting Colin Barnes, the abduction of his daughter Karli, the existence of his younger daughter Amanda, and Hunter’s determination to locate the missing child and arrest Reardon.
New scene set in the department canteen where the narrator meets Pete, Greg and Simon; personal revelation about his former fiancée’s death; assessment of Mercer’s current fragility and team debate over his involvement; introduction of “deniability” concerning the link between the Dyson murder and the Simpson case; decision to support Mercer’s lead and to locate Jodie and Scott before dawn.
Scott is captured and bound inside an abandoned stone building. A devil‑masked captor interrogates him, showing stapled sheets titled “Five Hundred Reasons Why I Love You” that stop at reason 274, and forces Scott to recount the first reason about how they met. A mysterious network message from “isz5jlm” appears; Scott replies, asking who the sender is. Later the captor returns with a heated screwdriver, asks Scott if he loves Jodie, and drives the screwdriver into Scott’s eye.