On this week's Person of Interest...

Root recruits Shaw for help in Alaska and Miami.

Finch calls on Reese to help protect a congressman in Washington, D.C.

Turns out, Decima is trying to get the congressman and the senator connected to Northern Lights to help move the way for the government to allow the use of Samaritan.

The Machine had assigned the number so Reese would kill the congressman and prevent Decima from activating Samaritan.

Finch convinces Reese not to follow through, and the group is forced to flee.

Decima gets its wish and enters in its first target: Harold Finch.