John, a young man raised by his aunt, is in love with Anna, a servant girl who is going to have his baby. He is willing to marry her but his stern aunt wants him to marry a rich girl. To separate the lovers, she arranges for her nephew to be enrolled at a university in a distant town. She then has Anna sent away to live with Torgus the coffin maker and his mother where she will be secluded until the birth of the child. Torgus, a clumsy golem-esque sort of fellow, is immediately charmed by the beautiful girl and takes pity on her. Meanwhile, Anna anxiously awaits John's return.

Die Ratten was produced by actress and singer Grete Ly. Her company, Grete Ly-Film, made five films between 1919 and 1921. Die Ratten, which is based on the play of the same name by Gerhart Hauptmann, was the last one. Hauptmann, one of the most important promoters of literary naturalism, had received the Nobel Prize for Literature in 1912. The screen adaptation of his play is beautifully photographed in a realistic style by Karl Freund, one of best German cameraman of that time who also worked with directors such as Lang, Murnau, Dreyer, Dupont and Ruttmann. Moreover, the cast of Die Ratten also acts in a very naturalistic way, far from the affected expressionistic style. Die Ratten was made on a modest budget, but the collaboration of an excellent team produced a film that was ahead of its time.

Deep in the forest lives the bitter Dr. Wislizenus, whose childhood sweetheart Maria committed suicide ten years ago. The visit of a childhood friend, he who wrote a poem about Mary, triggers a tragedy.