Undine works as a historian lecturing on Berlin's urban development. When the man she loves leaves her, the ancient myth catches up with her. But falling in love anew, Undine reworks the myth of the mysterious water spirit as a modern fairy-tale in a disenchanted world.

The company soldier Hannah and the scientists Gavin and Dimitri are researching an algae project on board the Rubikon space station, which is supposed to permanently supply humanity with oxygen and food. But suddenly the earth disappears below them in a brown, toxic fog and all contact is broken off - are they the last survivors of humanity? Should they initiate the safe station, dare the return flight and thereby risk their lives?