As Person Of Interest begins, Reese (Jim Caviezel) is a washed-up former CIA agent, presumed dead, who's drinking away his sorrow over the death of his wife. Enter enigmatic billionaire Finch (Michael Emerson), who has a simple mission for Reese: Help save lives. Using data from a supercomputer built to hunt terrorists in the wake of the September 11 terrorist attacks, Reese and Finch act only with a Social Security number and must determine how innocent people become involved in terrible crimes -- and what can be done to prevent them.