Chan Kwai-Bun, portrayed by Sean Lau, is a highly skilled detective endowed with a remarkable ability: the power to perceive a person's inner personalities or ghosts. However, his career takes a drastic turn when he mutilates himself—severing his ear and presenting it to his outgoing superior, which leads to his forced retirement.
Meanwhile, Inspector Ho Ka-On, played by Andy On, is trying to unravel the mystery surrounding Wong Kwok-Chu, a colleague who mysteriously vanished during a chase alongside his partner, Ko Chi-Wai (played by Lam Ka-Tung). Although Wong has been missing for a staggering 18 months, his firearm has been implicated in a spate of armed robberies. In light of this, Ho seeks the help of Bun, who now lives a reclusive life with his imaginary wife May Cheung, portrayed by Kelly Lin.
As Bun delves deeper into the case, he uncovers a shocking truth: Chi-Wai is not merely one man but rather a collective of seven spirits—each embodying a facet of the seven deadly sins. The primary spirit appears as a shrewd businesswoman. Bun theorizes that Chi-Wai’s gun has fallen into the hands of a suspect named Naresh Sherma and harbors suspicions that Chi-Wai murdered his partner Wong to conceal the loss of his own weapon.
During an investigation at the scene of Wong's death, Bun takes crucial evidence including Ho's gun, police identification, and even a vehicle to continue his pursuit of justice independently. When he encounters Ho again, he perceives Ho's inner self—a frightened, confused child—and shares his suspicions about Chi-Wai's involvement in Wong's murder intertwined with a conspiracy against Naresh Sherma.
However, Ho's attempts to apprehend Chi-Wai falter as he tries to prove that Chi-Wai carries Wong's murder weapon; his efforts are thwarted, particularly as Chi-Wai manages to manipulate police records. Compounding the tension, Ho begins to place trust in Chi-Wai.
Subsequently, the pair venture into a warehouse to track down Naresh Sherma. Unbeknownst to them, Bun is covertly observing and attempts to alert Ho of the looming danger, warning that Chi-Wai may have darker intentions. Unfortunately, Ho dismisses Bun's warning, leading to a catastrophic encounter within the warehouse, where a gunfight ensues, resulting in the deaths of Sharma, Chi-Wai, and Bun. In a tragic twist, Ho survives.
As Chan Kwai-Bun takes his final breaths, he glimpses Ho's inner child, receiving counsel from a female spirit, urging him to devise an alibi while Ho, similar to Chi-Wai, engages in the frantic rearrangement of firearms to fabricate a cover story.
