Plot summary
While Shaw is abducted by Root, Finch and Reese get the number of Timothy Sloan ( Kirk Acevedo ), an estate investigator. Finch goes undercover as Sloan's assistant while Reese continues investigating Shaw's whereabouts. Sloan investigates the case of his foster brother, a man named Jason Greenfield ( Michael Esper ), who apparently died of a heroin overdose. Finch soon learns that Greenfield used to be a member of the organization Vigilance, which includes Peter Collier ( Leslie Odom, Jr. ) (from the episode "Nothing to Hide"). Meanwhile, Shaw reluctantly agrees to help Root get into a CIA black site.
Jason, who is alive, is one of the people held there, awaiting transfer. The transfer is intercepted by Vigilance, leading to a shootout. Root helps Jason escape and tells him to go to a location in South America. Reese and Shaw eventually save Sloan and recapture Root, but Collier gets away. Finch locks up Root in the Library.
Credits
Adapted from Wikipedia contributors, Person of Interest season 3. HTML formatting and reference markers removed.