拳师差利与教练到日本参赛,结识了当地黑帮山冈组首领横田及其女歌子.横田在黑帮斗争中被杀,其妻宏子接任,为安全计将歌子送到香港交差利照顾。因受大川组逼害，宏子向差利求救，差利求助于力奇及王三，最后决定用毒品交换军火，提供日本的宏子。宏子被袭受伤，歌子独返虎穴探母，差利、力奇急忙赴日援助。

Michael Chan plays Charlie Chan, a boxer who goes to Japan to take on a local hotshot in the ring. A gang of yakuzas pressure him to take a dive, but Charlie beats his opponent senseless instead, resulting in a life-or-death chase in which Charlie and his coach try to escape from the angry gangsters. They are spared by the yakuza boss Yakoda, and their eagerness to impress him leads them to pretend that they are the leaders of an influential triad organization known as the Marlboro Gang. That gang doesn't really exist, and their ruse only leads them to further endangerment after Yakoda is murdered by one of his employees. Yakoda's widow sends their daughter (who speaks Cantonese) to Hong Kong so that she won't be next on the hit list, and Charlie -- still pretending to be a powerful triad gangster -- agrees to protect her. He and his friends must save the girl from assassination attempts and kidnapping along the way, as well as coming to the rescue of Yakoda's widow.