莎朗(詹妮弗·洛佩兹 Jennifer Lopez 饰)是一位精明强干的女警,被安排到了犯罪率最高的芝加哥南部地区,在那里行使她惩奸除恶弘扬正义的责任和权利。虽然莎朗在事业上干得十分出色,深受上司和同事们的信任和赏识,但她和家人之间的关系却十分淡漠。更糟糕的是,曾经的一 段痛苦的回忆一直笼罩着莎朗,令她时时陷入绝望之中。 凯奇(吉姆·卡维泽 Jim Caviezel 饰)是一个游荡在城市街头的失意人,他关照陌生人和邻居,在一次警匪追逐中意外救下莎朗,两人由此相识。然而,过去的一场灾难让他失去了妻子和女儿,同时逝去的还有他的记忆,这使得凯奇十分痛苦。在莎朗的帮助之下,凯奇终于鼓起勇气决定寻找惨剧的真相,与此同时,莎朗那灰暗的过去亦渐渐浮出水面。While pursuing a suspect one night, Chicago Police officer Sharon Pogue nearly becomes the victim of a fatal ambush. A mysterious stranger, Catch intervenes, disarms the assassin and saves Sharon's life. Is it a stroke of luck? A twist of fate? Or just a concerned citizen who happened to pass by at the right time and wasn't afraid to get involved? Maybe, but Sharon and Catch have met once before. As the two fall in love, they discover the truth about each other and are forced to deal with the secrets from their past.