Director Alejandro Gonzalez Iñarritu and screenwriter Guillermo Arriaga follow up their masterful Amores perros with another complex drama of disparate characters whose lives are linked by fateful misfortune—not nearly as panoramic or rewarding as the earlier film, but just as intimate and deeply felt. Naomi Watts is excellent as a woman whose husband (Danny Huston) and two daughters are killed by a hit-and-run driver; the haunted culprit (Benicio Del Toro), an ex-con and hard-core Christian, agonizes over whether to turn himself in, while the man who receives a transplant of the husband's heart (Sean Penn) goes in search of the wife to give thanks. As in Amores perros, Gonzalez Iñarritu and Arriaga slice and dice the chronology, which helps distract from the warmed-over story elements and focus attention on the superior performances. With Melissa Leo, Charlotte Gainsbourg, and Clea DuVall. R, 125 min.