Filmmaking workhorse Clint Eastwood takes a seemingly routine genre exercise – an adaptation of a mystery novel by Dennis Lehane – and makes it something all his own, in this case another of his meditations on the ripple effect of violence. Mystic River follows three childhood friends (Sean Penn, Kevin Bacon, Tim Robbins, all excellent) who are uncomfortably united by a shared tragedy from their youth and a recent murder. It’s a thriller steeped in sorrow rather than plot twists.