In the lower depths of human societies, the Dirty Rats, or Big Circles are lurk in the shadows of society. Block Head who dotes on his son and tolerates his nagging wife. Chung who is ever so kind to his grandmother. Chung who still loves childhood sweetheart Ah Sheung, now a cabaret hostess. And Rooster And Bull's Eye. Their leader is Tung who has a perfect plan for a "job" in Hong Kong. In 48 hours, they are to cross the border, rob a jewelry shop and then get back across the border....