The hottest summer in years: Meteorologist Jan returns from Oklahoma, where he has studied twisters up close, after faring a traumatic catastrophe during his dangerous research. Back in Berlin, he comes to face with his past and his ex-girlfriend Eva, who he had left behind. He clashes with his father, head of the local weather institute, and only his blind sister Sophie still seems to trust him. But no longer is Jan in town that an unusual cold front approaches the city. Immediately Jan recognizes the familiar warning signs of impending doom.

More than once Karin Ugowski has surprised with her versatility, as shown again in the more recent years, like in the cinema short film Open (2005) of the director Charlotte Siebenrock, when she turned from an old frustrated canteen kitchen porter into an attractive buoyant and beautiful looking women within minutes, leading to the presentation of the short film at various short film festivals...

In extreme emergency, Bernd Roland and Toni Burian have to leave the moving train on the free route. Bernd Roland is injured when jumping. But he manages to stop a hospital car and give the order to take him and Burian to Berlin. Having arrived in the capital, Roland, Burian and the Soviet scout Boris (Gunter Schoß) do everything in their power to successfully complete their instructions. In concrete terms, this means finding out what plans the SS has for the last battles for Berlin.

Secret operations unit "Spree" was the sequel to the scout films “Secret operations unit Boomerang” (1966) and “Secret operations unit Ciupaga” (1967). In the spring of 1945 it was definitive: the final defeat of fascist Germany was inevitable, only a few weeks left, then the Hitler regime would be history.