Plot summary
Riley Cavanaugh, an enforcer for an Irish mobster, becomes the next number when he betrays his boss and goes on the run with his lover, Annie, whom he was ordered to kill. Reese and Finch debate the morality of trying to save a ruthless killer, but they soon need Riley's help when Annie is captured by bounty hunters hired by the mob. To keep Annie safe, Finch is forced to make a deal with Elias, who continues to run his criminal organization from behind bars, in exchange for a game of chess.
Elias uses his influence to order the hit called off, but the mobster continues to personally pursue the couple. Riley sacrifices his life in order to save Annie, an act Reese encourages her to interpret as proof of his love and a sign of his redemption. Reese later tracks down the hitman who killed Riley and presumably kills him in retaliation.
Credits
Adapted from Wikipedia contributors, Person of Interest season 2. HTML formatting and reference markers removed.