"21 Grams" is shown in a series of out-of-order scenes. Cristina Peck (Naomi Watts) is devastated when her husband and two daughters are killed after being hit by a car. She begins using cocaine and struggles to get her life in order. Later, she learns that her husband's heart has been donated to Paul Rivers (Sean Penn). She meets Paul and begins a relationship with him. At the same time, she becomes obsessed with getting revenge on the man who killed her family, Jack Jordan (Benicio Del Toro), a Jesus freak and ex-convict. Jack is overwhelmed with guilt; he was never legally punished for the crime, which his wife helped him hide.