There is no such thing as a completely locked room File 2 / Please don't drown in this river File 1 (S01E08)

Kageyama uncovers a hidden passage that leads him closer to unraveling the locked-room murder mystery. Meanwhile, Reiko finds herself cornered by a crazed woman brandishing a knife, leaving her with no chance to flee. In the following case, the body of a journalist dressed in white is found by the riverbank. Surprisingly, despite being dry, he died from drowning. It turns out he had been in debt and had set his sights on a famous "Shaketopia" actress whom Reiko had idolized during her childhood.