电影改编自《华盛顿邮报》战地记者丹尼尔·珀尔的妻子所写的回忆录。丹尼尔（丹·福特曼 Dan Futterman饰）前往巴基斯坦调查报道一桩恐怖分子的新闻，却不幸遭到绑架，不久后惨遭杀害。妻子玛林娜（安吉丽娜·朱莉 Angelina Jolie饰）却一直在祈求丈夫能平安归来，寻找丈夫的信念一直支撑着这个已有着身孕的准妈妈。

她坚毅地书写回忆录，里面布满着和丹尼尔相识相知的点滴，更令丹尼尔的新闻理想和奔赴真相的勇气跃然纸上，她要让孩子知道，自己的父亲，曾经是一个称职的新闻人。玛琳娜终于能够坚强而平静的接受丈夫的遇害，同时，她不仅要让孩子远离种族仇恨和战争烟尘，还回到法国继续自己的事业，抚养孩子长大成人。

For five weeks the world waited for news about Danny Pearl, the Wall Street Journal reporter who was kidnapped in Karachi, Pakistan And then came the broadcast of his shocking murder. The complete account of his abduction, the intense effort to rescue him, and the aftermath are told here--in astonishing detail, and with courage and insight--by his surviving wife, Mariane.

A Mighty Heart is the unforgettable story of two journalists who fell in love with their work--and with each other. Together, Mariane and Danny Pearl traveled across the globe, dedicated to journalism that increases the understanding of international politics and of ethnic and religious conflict. In the end, Danny was caught in the dangerous fissure where warring cultures, politics, and ideologies collide. A Mighty Heart is both a portrait of a partnership built on the ideals of love, truth, and justice and a critical look at the methods and structure of the AI Qaeda network.