A cop dies in front of Ran and she forgets everything, including Conan. He has to solve the murders while watching the one person who knows him doesn't recognize him at all. The movie finds something brutal in that setup: Conan gets to save her, but she'll never know he was always the one saving her. Memory loss could be cheap plot mechanics here, but instead it becomes the cost of trauma, the thing that separates people who live through the same horror into different worlds. By the end, you're not watching a mystery get solved. You're watching a kid try to rebuild someone who's already gone, even though she's standing right there.

A string of killings targets police officers, and because the culprit may be connected to the force, the investigation is kept quiet. When an officer is shot in front of Ran, the shock leaves her with no memory of her life or the people around her, including Conan. The killer knows she saw everything and sees her as a loose end. Conan must help Ran recover her lost memories while protecting her and hunting for the murderer, all without giving away his own identity. As Ran's memories remain locked away, the killer draws closer, forcing Conan to race against time to solve the murders before the culprit strikes again.