A baby just a few hours old is found in a basket floating on Lake Constance - wrapped in a sheet smeared with mysterious historical symbols. When a DNA analysis reveals the mother to be Rita Hafner, who disappeared without trace six months ago and was presumed dead, Oberländer and Zeiler have to admit to having made mistakes in the course of their police work. When, parallel to the resumed search for Rita Hafner, another murder occurs and Zeiler unsuspectingly falls into the clutches of the perpetrator, both Oberländer and Komlatschek find themselves forced to overstep their bounds.