It was a devastating day for Arnold and his wife, Karen when their son, Christian, a soldier in the German armed forces, told them he was going to be deployed abroad. Everything is different now. Arnold has decided to retreat to a secluded mountain hut in Tirol along with his dog in order to finally find some peace of mind. Barely has he reached his snow drenched destination, when he discovers the threatening traces of an intruder. While ruminating over the news of his son and the conversations he had with his wife, Arnold must also battle against an unknown fiend if he wants to save his own life.

Arnold Stein si è ritirato in una capanna di montagna per trovare la pace dopo la morte di suo figlio, arruolatosi nell'esercito e deceduto in terra straniera. L'isolamento di Arnold verrà interrotto quando uno sconosciuto comincerà a terrorizzarlo.

"Fremder Feind" erzählt die Geschichte von Arnold Stein - einem Mann, der alles verloren hat. Arnold lässt sein altes Leben zurück und zieht sich mit seinem Hund in die Einsamkeit einer abgelegenen Berghütte zurück. Doch in der Bergidylle findet Arnold keinen Frieden. Ein Fremder beginnt ihn zu terrorisieren und zum ersten Mal in seinem Leben nimmt Arnold den Kampf auf.

Un homme part s'installer dans une cabane en montagne avec son chien en plein hiver. Des flash-backs viennent éclairer peu à peu ses motivations et sa vie d'avant, auprès de sa femme déprimée et en contact avec son fils parti faire la guerre.