Award-winning film by the director of 'Amores Perros', Alejandro González Iñárritu. Shot mainly with a hand-held camera, and following a non-linear plot line, the film captures the immediacy and confusion of the moments before, during and after a horrific accident that causes the lives of three disparate people to become interwined. Sean Penn plays Paul Rivers, a mathematics teacher facing up to his pending death from a heart problem, while his distant wife Mary (Charlotte Gainsbourg) hopes to become pregnant from artificial insemination. Naomi Watts is Cristina, mother of two little girls who has overcome a drug-dependent past to achieve a stable, happy marriage and family life. Benicio del Toro plays Jack Jordan, an ex-criminal who has now found Jesus and is struggling to provide for his wife and their two children in a poor area of the town. When tragedy strikes, all three characters must re-evaluate their lives in the face of death. The title refers to the 21 grams a person loses at the moment of death, thought to be the weight of the human soul.