In the south of Laos, an American volunteer doctor becomes a fugitive after he intervenes in the sexual assault of a young woman. When the assailant's body is pulled from the Mekong River, things quickly spiral out of control.

金波医生（Harrison Ford 饰）的妻子在家中被人谋杀，虽然金波当晚撞见独臂凶手并与之搏斗，但是凶手终于逃走，金波本人却因种种不利证据被判定为谋杀罪。在押解前往监狱的途中，一名犯人试图逃脱造成