Konrad and his extremely annoying cousin are not the only ones who are curious about the bunker at the beach. That place seems to attract people like a pile of horse manure attracts flies! What are they all looking for? Gold? And whose corpse is that? Konrad and Lisbeth run into many strange things this summer on the French Atlantic coast, yet lastly it is the family's own secret that shakes everyone up.
Everything is Konrad's fault – probably even the fact that the seawater is salty. But having to spend his vacation with his prodigy cousin, Lisbeth (who does back dives into the pool and won the math olympics) really tops things off. Never mind. At any rate, Konrad and Lisbeth also feel drawn to the cement bunker and want to take a closer look. They not only discover the Blue House when doing so, they also stumble across some peculiar mysterious documents originated from dark times and closely guarded family secrets. These are first revealed when the mystery of Lisbeth's disappearance is solved! A wonderfully thrilling new novel that is full of suspense – and once again proves what a “literary champion” (Süddeutsche Zeitung) Martina Wildner is.