Paul Rivers, an ailing mathematician lovelessly married to an English émigré; Christina Peck, an upper-middle-class suburban housewife and mother of two girls; and Jack Jordan, a born-again ex-con, are brought together by a terrible accident that changes their lives.
Acting
Naomi Watts delivers career-best unraveling; Penn and Del Toro devastate.
Editing
Chaotic timeline forces you to feel disorientation of trauma.
Direction
Iñárritu's relentless close-ups refuse you emotional distance.
Director
Alejandro González Iñárritu
Trivia, insights & behind the scenes
The title refers to a 1907 experiment claiming the soul weighs 21 grams—scientifically debunked but poetically irresistible.
Iñárritu filmed entire scenes in single takes, then shattered them in editing to mirror psychological fragmentation.
US
