The Intruder

Catherine is determined to uncover Stella's fate and the truth behind Nick's past, even as evidence vanishes and her grasp on reality feels precarious. Her love for Nick becomes strained by jealousy and fear, driving her to extreme actions in self-defense. She navigates diary clues, shifting timelines, and possible wormhole interference to discern what really happened.

Nick is a widower who clings to Stella's memory while trying to protect his new marriage. He loves Catherine but remains guarded about his late wife and the rumors surrounding infidelity. His cautious demeanor and hidden past contribute to the mounting distrust and tension between him and Catherine.

Daisy is Charlie's on-and-off girlfriend who becomes entangled in the couple’s spiraling mystery. Her presence adds strain and serves as a flashpoint for suspicion and danger within their social circle. Her eventual death deepens the sense that the stakes are personal and escalating.

Badge is an art broker and Nick's former girlfriend who resides in the loft below Catherine and Nick. She lends Catherine a pistol and becomes a crucial link to Nick's past. Her involvement complicates loyalties, as she moves between ally and potential obstacle.

Charlie is a mathematician and video game programmer living in the same building. He offers a rational perspective amid rising tension, but he is drawn into the dangerous events surrounding the couple. His death adds a sharp, personal cost to the unraveling mystery.

Stella is Nick's deceased wife whose memory and diary entries drive jealousy and suspicion. Her past presence resonates through Catherine's present, acting as a catalyst that provokes questions about motive and truth. She remains a ghostly influence rather than a living character in the film.

Detective Fordham leads the investigation and remains skeptical of Catherine's story. He represents procedural caution and the drive for conventional proof, challenging Catherine to prove a narrative that may defy easy evidence. His role heightens the contrast between belief and disbelief in the investigation.

The saxophonist adds texture to the building's ambience, reflecting the urban setting and social dynamics surrounding the central couple. His presence contributes to the moody, atmospheric layer of the story.