“21 Grams” is a 2003 drama film directed by Alejandro González Iñárritu and written by Guillermo Arriaga. The film stars Sean Penn, Naomi Watts, and Benicio del Toro in lead roles. The title of the film refers to the idea that the human soul weighs 21 grams, which is based on a scientific study that was conducted in the early 20th century.

The film tells the interconnected stories of three individuals whose lives are shattered by a tragic accident. Paul Rivers (Sean Penn) is a mathematics professor who has a terminal heart condition. Christina Peck (Naomi Watts) is a former drug addict who is trying to put her life back together. Jack Jordan (Benicio del Toro) is an ex-convict who has found religion and is struggling to provide for his family.

The film is non-linear in its narrative structure, with events unfolding out of chronological order. The audience is gradually shown how the three main characters are connected to each other and how the accident has impacted their lives. The film received critical acclaim for its acting performances, direction, and writing, and was nominated for several awards, including two Academy Awards.