Absturzmomente by Jörg Rosenbauer

You climb a mountain without any equipment and plunge down into the depths. The free fall ends in a pact with a voice from beyond: To spare your life you have to save some person's life. Henceforth, you have to prevent a murder in a house without being able to directly intervene into the action. »Absturzmomente« scored the fourth place in the German interactive fiction Grand Prix 2010.

The author's website for the game, including download of the babelized story file, is here (used hosting service doesn't allow hotlinking).