Steve Tomlin an undercover cop in Danny's precinct is shot and killed and someone at the precinct clears out his locker before the Captain can do it. Turns out another officer was trying to protect Tomlin's family from finding out her had a girlfriend with a baby.
Danny's investigation shows that Steve's widow knew he was cheating on her. She called a phone number and thought she was speaking to the girlfriend. The phone number was part of Steve's undercover operation and the wife accidentally told the drug dealer that he was a cop. Two days later Steve was shot and killed. Frank chooses not to tell the wife what really happened.
With no benefits going to the girlfriend and child, Frank asks Henry to work on a "back pocket pension."
Nicky asks both her mother and Jamie to help find former classmate Tyler when she thinks he's living on the streets. Turns out Tyler is looking for his mother who is a junkie. Erin tracks down the mother in a hospital and helps get Tyler off the street.