Victorian London. A certain Doctor Bertrand Mort drowns in the Thames with a mangled arm and a bullet wound in his chest. Actually, he is not against taking his own life. But then he notices how a certain girl throws a bundle with a crying baby into the water. Forgetting about everything, Bert saves the child and finds his mother - the poor young seamstress Mary, who was kicked out into the street the day before by the owner of the apartment. The three of them settle in the docks of Lambeth. And everything would have turned out well if it weren’t for Bert’s terrible secret and a small silver object in the shape of a jellyfish that turns Mort into a devil.