The first half of The Deep End of the Ocean, with Pfeiffer and Williams as parents whose 3-year-old son vanishes, is almost unbearably wrenching. It begins in a desperate panic, then gets grimmer as hope fades to despair. Far less effective, however, is the rest of the story, set nine years later, when the boy resurfaces. Adapted from Jacquelyn Mitchard's novel, the screenplay delves into a messy mix of post-reunion emotions, only to clean up each conflict too quickly and glibly. (Can a long-lost brother's abandonment issues really be resolved with a game of one-on-one?) But if the film was less than satisfying as a big-screen event, it's still worth renting for Pfeiffer, who valiantly portrays the devastating complexities of grief and guilt.