Philipp Gabert and his best friend, Dr. Nicolas Amberg, are hiking in the mountains. Suddenly, Philipp suffers a strange attack of weakness and loses consciousness. Nicolas is only just able to prevent his fall. But the friendship between the two men is burdened by a problem: Nicolas is secretly in love with Philipp's wife Julia - and feels like a traitor. When the men set off on another mountain tour, only one of them returns. Was it an accident or murder?