There Is No Such Thing as a Completely Locked Room: File 2 / Please Don't Drown in This River: File 1
Kageyama locates a secret passageway to solve the locked-room murder mystery. Upon encountering a deranged woman wielding a knife, Reiko is left with nowhere to escape. On the next case, a white-suited journalist's body is discovered by the river. Despite being dry, his cause of death is drowning. With debts to pay, he had targeted a well-known "Shaketopia" actress whom Reiko adored as a child.
Aired 23/05/2025EP 8 - There Is No Such Thing as a Completely Locked Room: File 2 / Please Don't Drown in This River: File 1

The Dinner Table Detective
Rich heiress Reiko Hosho lives a double life as a novice detective, fighting crime under Inspector Kazamatsuri—also from a wealthy family. After work, Reiko sheds her pantsuit to don a lovely dress for dinner each day. Difficult cases force her to confide in her butler Kageyama, who proceeds to savagely ridicule her inability to solve mysteries, all while brilliantly unraveling each case himself.
(Source: Amazon Prime Video)