21 Grams is a 2003 American drama film directed by Mexican director Alejandro González Iñárritu from a screenplay written by Guillermo Arriaga. It stars Sean Penn, Naomi Watts, Charlotte Gainsbourg, Danny Huston and Benicio Del Toro.
The second part of Arriaga's and González Iñárritu's Trilogy of Death, preceded by Amores perros (2000) and followed by Babel (2006), 21 Grams interweaves several plot lines in a nonlinear arrangement.
21 Grams revolves around the consequences of a tragic automobile accident. Penn plays a critically ill mathematician, Watts plays a grief-stricken mother, and Del Toro plays a born-again Christian ex-convict whose faith is sorely tested in the aftermath of the accident. The three main characters each have "past", "present" and "future" story threads, which are shown as non-linear fragments that punctuate elements of the overall story, all imminently coming toward each other and coalescing as the story progresses.