On this episode of Person of Interest...

Finch, Fusco and Root try and figure out why the Machine didn't notify them of an attack on one of Elias' men by the Brotherood. They eventually learn it was a crime of opportunity, not premeditated.

Reese gets a number involving a man connected to a homicde case Carter took on years ago.

Reese looks into the old case as flashbacks reveal Carter looking into it.

Flashbacks also reveal Reese talking with Carter on a stakeout.

Reese is shot, but he manages to shoot the real killer. He talks with Carter, a hallucination, about opening up and their paths.

A car arrives at Reese's location.