With Reese locked up in Rikers as Agent Donnelly struggles to figure out who the real 'man in the suit' is, Finch is left to his own devices to protect this week's POI, a high school student named Caleb Phipps. At first glance, Caleb appears to be a thoroughly average kid, but when Finch goes undercover as a substitute at Caleb's school, he learns that Caleb is remarkably good with computer code. Caleb gets involved with some vengeful drug dealers so Fusco and Finch try to keep him away from harm as he puts the finishing touches on a new memory software that could make millions of dollars. Gradually, Finch learns that Caleb's older brother died in a subway accident, and that Caleb feels responsible for it. He intends to sell his program and then commit suicide, but Finch is able to talk him out of it before he can go through with it. The two share an unspoken connection, which is clarified in flashback as we see echoes of Caleb's relationship with his mother in young Finch's interactions with his Alzheimer's afflicted father.
Meanwhile, Carter struggles to locate and dispose of the DNA evidence that the Feds have on Reese, hoping that it will be enough to get him out of Rikers after 72 hours. When Donnelly learns that the DNA has gone missing, he gets the Attorney General to sign a Public Safety Exception, giving him the power to retain Reese and the other three suspects indefinitely. He then tells Carter that she'll have to interrogate the men to find the real 'man in the suit.'