Plot synopsis: With the border between Austria and Germany running through its waters, Lake Constance provides the setting for a series of murder investigations. Beneath its scenic shores lie crimes with roots in the region's history, local folklore and long-standing family feuds. Working alongside his Austrian colleagues, German detective Micha Oberländer follows the clues, pieces together the circumstances behind each murder and uncovers secrets that often reach back generations. Meanwhile, changing partnerships and shifting alliances within the team add their own tensions and complications.