Buddhist retreat, China. Chen, an idealistic young monk, decides to go to England to preach the Buddhist doctrines of peace and non-violence. Before he leaves, an English teacher tries to warn him against trusting too much in human nature. But Chen is not dissuaded.
Chen disembarks at Tilbury Docks in London. Almost immediately he is swindled of his money and, when he tries to preach to the public, is heckled and racially taunted. His bad luck continues until eventually he loses his faith and is reduced to a miserable drunk. His only piece of good fortune is to find work in a Chinese curio shop located near the slums of the East End.
One day on his way to work, Chen spies a beautiful girl through a dirty window. The young girl, Lucy, lives with her sadistic, tyrannical father, 'Battling Burrows', a sometime wrestler and regular drunk. Her life is harsh, with no respite from slums, drudgery or brutality except through her daydreams and the memory of her dead mother. To Chen, Lucy is like a frail, delicate blossom and he delights in following her through the slums. However there is someone else tracking Lucy, a grim-faced Chinese man called 'Evil Eye'.
Burrow's manager has lined up a fight, and orders Burrows to give up alcohol in preparation and move to the training gym the following day. Burrows, as usual, takes out his frustrations on Lucy. He demands that she prepares his last meal by 6pm and that she should not leave the house. But when Burrows goes out to the pub, Lucy sneaks out.
Unfortunately Burrows returns before Lucy. He beats her until she falls unconscious. Burrow goes off to the training camp. When Lucy revives she staggers out of the house and collapses at the edge of the docks. Chen finds her, picks her up and carries her to his flat above the shop, where he showers her with care and kindness.
Meanwhile, at the training gym, Burrows, exasperated by the enforced drinking ban, sends one of the gym hands to his house to fetch a bottle of whisky. The gym hand brings back news that Lucy has been living with a Chinese man for the last three days. Burrows is apoplectic with rage. He vows to take care of both the girl and the Chinaman after the fight.
Burrows wins the fight, celebrates in the pub and, gathering together a posse of men, marches towards Chen's shop. Unaware of the trouble coming his way, Chen leaves the house to buy a flower to cheer up Lucy, who has been feeling a gloomy foreboding. The posse wrecks the shop and sets it on fire, while Burrows drags Lucy home.
Lucy tries to evade her father by locking herself in a cupboard. Burrows smashes the door with an axe and gives Lucy a severe blow over the head. Chen arrives and, seeing the girl unconscious and Burrows drinking, he kills Burrows. Lucy dies in his arms.
Chen takes Lucy back to the shop and places her in front of the shrine to Buddha that is now in flames.
