S8, E7: It is not unusual for an inmate not to return from day release. But when his prison officer disappears with him, it's a case for the Missing Persons Unit. Especially when the inmate, Carsten Rielke, is pulled out of the lake Plötzensee shortly afterwards, dead. His companion Murat Töplin, however, remains missing – was he perhaps not quite the model officer portrayed by his wife and colleague? The investigators find out that Töplin smuggled drugs into the prison to solve his financial problems. In addition, there seems to be another connection between him and the murdered Rielke. The latter was in prison for embezzling millions. It stands to reason that the beneficiaries of the millions are at large and responsible for Rielke's murder. This could make Toeplin next on the death list.