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.