It has been 10 years since Charles MacKenzie Jr. ("Mack") went missing. A Columbia University student about to graduate, he walked out of his apartment without a word and has never been seen again. However, he does make one ritual phone call to his mother every year on Mother's Day. Each time, he assures her he is fine, resfuses to answer her frantic questions, then hangs up. Even the death of his father in the tragedy of 9/11 does not bring him home nor break the pattern of his calls. His sister, Carolyn, is intent on searching for his whereabouts. Can this search for truth lead to deadly confrontation with someone close toher whose secret he cannot allow her to reveal?