The film's sets were designed by the art directors Karl Weber and Erich Zander.

On a rainy night a German Shepherd appears to be wandering aimlessly down the sidewalk when he bumps into detective Harry Peters.

While Harry stays behind, Greif picks up the trail and quickly confronts the crooks.

Kruppack fires a gun at the officer and then runs off, with the police dog Greif at his side.

In the meantime, Emil Kruppack has hired a shady character to kill Greif, since the dog’s behavior would sooner or later betray him to the police.

It turns out that Gerda and Kruppack know each other, because the young woman had once filed charges against the crook, who then swore revenge on her.

When Müller sees the police, he immediately tries to flee, but runs straight into Peters' arms.

Greif drags himself into a side room where Harry finds his best friend dead.