In 1986, police discover a grisly crime scene: a family shot in their beds at point-blank range. The mystery deepens when a sole survivor appears.

A calm, bespectacled suspect reenacts the massacre and says an odd entity made him do it. But his lawyer has a theory about a real motive.

Observed at a psychiatric hospital and composed in court, the accused remains a locked box and offers few clues. Now the therapist revisits his case.

His lawyer has his own ideas while his chronicler glimpses his real feelings. Can the truth about the past — or an enigma's present — be understood?