Brother and sister, Tom and Bobby, are orphans growing up rough, with their dog Tag, in the Victorian East End of London. Helped by Dr Barnardo, they have begun to make progress when Bobby is attacked in the notorious Rookeries. Tom comes to the rescue but finds himself arrested, in a cell, and then before the Beak. His trial is at the Old Bailey where he is not allowed to speak in his defence. Then Tag comes to his rescue!