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?

Bax needs to take a break from Valais and therefore decides to open a smoothie kiosk in Bern. Pirmin, now a full-time father, is instead following a case of murder disguised as suicide, while Valmira is on the verge of breaking through, but the catch is around the corner.

Pirmin's investigation turns out to be a complete failure. Bax is in fact too busy saving his colleague Julie from a love scam and also has to face an unexpected tragedy. Meanwhile, Fricker, now bankrupt, causes one of his workers to fall into a deadly trap.

Bax is suspected of murder, but during a prisoner transport he manages to escape together with Juni. The two thus end up in an uninhabited region, finding themselves without water and without escape. For his part, Pirmin instead has to get rid of a corpse, while Valmira realizes that she has been deceived.

Bax and his gang come across Smetterling in the Pfyn woods, where he is hiding and is busy hunting down mafiosi. When the criminals show up, the time of reckoning finally arrives. What the cops don't know, however, is that the criminals have Valmira in their grip.

Valmira lures the mafiosi into an ambush with fatal consequences, while to get to the bottom of a double murder the cops infiltrate the heart of the Swiss secret services. Despite constantly having two Romande policemen on his tail, Pirmin's son will prove fundamental in solving the case.

Due to the housing shortage in Valais, Bax settles in Pirmin's garage, much to Regina's dismay. Meanwhile, Valmira has not yet given up on her dreams of glory and Juni does everything he can to help her realize them.

Bax is seriously injured during a fight: will he be able to reach the hospital in time? Meanwhile, the babysitter Nadira is in grave danger, while Valmira seems willing to do anything to get a collaboration with a rap star.

Bax and Pirmin discover that Regina is leading a double life, also uncovering other clues that reopen an old case. Nadira is instead hunted by a ruthless assassin, while Valmira finally realizes her dream, but at a very high price.

Cornered, Regina finally confesses that she is on a secret mission for the government. Meanwhile, the bumbling Bax makes another mess of his own, sparking a full-blown international crisis.

In an abandoned power plant, Bax and Pirmin find themselves fighting to save the world from impending doom. However, their mission becomes complicated when they must also free Nadira from the clutches of a relentless bounty hunter.