Bax and Pirmin track a killer to the Christ Roi statue high above the Rohne valley where they witness a strange ceremony of a sect. Valmira becomes the target of mole Gerda and Juni comes to the Tschuggerposten with a mysterious key.

Bax is on the run from his own colleagues. Alone with his mother, he persuades intern Smetterling to commit a burglary in order to exonerate himself. Valmira has been kidnapped and the kidnappers demand the DVX key from Juni, otherwise Valmira will die.

Bax and Smetterling find the decisive clue to the plans of the sect. Apparently, the cult wants to blow up the Grande-Dixence dam and flood the entire Valais region. Valmira doesn't let her kidnappers get her down and Biffiger's curiosity puts him in mortal danger.

The police believe that Pirmin murdered his father-in-law. Gerda, the actual perpetrator, wants to get the explosive key from Bax - no matter what the cost. Bax is handcuffed and cannot defend himself and Valmira is in mortal danger.

Bax and Pirmin cannot prevent the countdown to the explosion of the dam wall. With the latest technology, huge guns and a superhuman effort, the Tschuggers try to stop the catastrophe. Will they save the Valais from the end of the world?