A young nobleman named Eugene, the second son of the prestigious Hartman family, is arrested for the massacre of his entire household. From his cell, the 21-year-old requests a meeting with the detective who captured him, Kevin Kisaragi Jr. Eugene claims he is innocent and asks for help in capturing the real culprit. His plea conceals an unbelievable secret: Eugene is a user of magic.

This is the central premise of Mahōtsukai no Hanzai Sōsa, a buddy mystery series from creator Yoko Tamotsu, known for Midnight Occult Civil Servants. The story follows the unlikely partnership formed between the imprisoned magician and the young detective. Despite being the one who put Eugene behind bars, Kevin, an upright and justice-driven officer, agrees to work with him. Together, they begin investigating the truth behind the Hartman family murder, with Eugene driven by a vow to exact revenge on the real killer.

The two main characters form the core of the narrative. Eugene Hartman, a magician falsely accused of a horrific crime, possesses both magical abilities and a personal stake in solving the case that condemned him. Kevin Kisaragi Jr. serves as his pragmatic counterpart. While he is an excellent detective with a strong sense of justice, Kevin also harbors a unique physical trait that becomes a crucial element in their dynamic.

The overarching plot focuses on the investigation of the Hartman family massacre, forcing the pair to delve into a mystery that involves the highest echelons of magical society. As they work as a team, the series explores the friction and growing trust between a convicted criminal and the lawman who caught him, all within a world where magic exists and is a factor in criminal investigation. The story is serialized in Comic Newtype, and the complete series spans five volumes.