While Zeiler has still not returned from her vacation, Oberländer has problems getting used to her replacement, the resolute Detective Hoffmann from Vienna. But soon a complicated murder case forces them to cooperate.

Plagued by nightmares and strange visions, Detective Oberländer is suspected of murder.

Just as the freediver Victor is about to start a new record attempt, the body of his wife is found in the depths of Lake Constance. Detectives Oberländer and Hoffmann suspect that Victor himself may have been responsible for the drowning of his wife.

When Hoffmann’s past catches up with her, not only is the relationship with Oberländer put to a test, but also the safety of her family is severely threatened.