朱莉(克里斯蒂·麦克尼科尔 Kristy McNichol 饰)是一名女演员,一次意外中,她驾车撞伤了一只狗,四处求医无门又不忍心弃之不管的朱莉最终决定将狗收留。有狗狗陪伴在身边,朱莉的心中多了一份安全感,当她看见狗和入室抢劫的歹徒英勇搏斗之后,朱莉更是对这只勇敢的动物充满了信任和依赖。 随着时间的推移,朱莉发现对自己忠心耿耿的狗对黑人却有着超乎寻常的强烈攻击性。原来,在幼年时期,狗曾经经受过十分残酷的训练,用以将它变成攻击黑人的“武器”,为了恢复狗纯良的本性,朱莉找到了驯兽师查理(塞缪尔·富勒 Samuel Fuller 饰)驯化狗。经过不懈的努力,查理的训练终于初见成效,不幸的是,意外还是发生了。Deprogramming a dog who kills Blacks is the ultimate challenge for an unorthodox African-American trainer. When a young Hollywood actress finds the injured stray, she nurses it back to health, not knowing it's a "White Dog" trained by a racist to attack only Blacks. Julie's appalled when the otherwise gentle, white German Shepherd breaks out, then returns from his nighttime foray dotted with human blood. Julie desperately races from trainer to trainer, advised to kill her pet, until the top Hollywood canine expert refers her to his former protégé, Keys.