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.