Paula is back on earth. After months in orbit, she has returned to the planet. Now a short flight across the ocean and she is with her family. But Paula never arrives home. Sven and his daughter Charlie wait in vain at the gate. The plane has disappeared from the face of the earth.

While Sven tries to protect his daughter from the terrible realization, he grasps at every straw he can find. And suddenly, it seems, he finds what he is looking for: Paula has left him a riddle, a red thread that Sven is now following. But the more he pulls on it, the more his life collapses, the greater the mystery and the threat to him and Charlie, and ultimately to the whole world. Because Paula was on the International Space Station. And there, in the darkness of space, she has made an incredible discovery.