A advanced training weekend with team trainer Simon Fröhlich takes Lena Odenthal and her colleagues Johanna Stern, Peter Becker and Ms Keller to a remote hotel in the middle of the Black Forest. Upon arrival they immediately realize why the deal was so inexpensive: the good old days of the Lorenzhof are long gone. The two people who run the place, Bert Lorenz – called Humpe – and his niece Doro, are every bit as strange as their long-term hotel guest, the aged actress Lilo Viardot.

At first, the police commissioners are not deterred, but when, one night, they discover a human bone in their dinner and find out from the local police couple, Jörn and Elli Brunner, that Humpe spent 12 years in prison for murdering his sister-in-law, their curiosity is aroused.