Jamie had been working late one night when he finds out that there was a female police officer in his precinct that working under cover for two years. He was getting ready to leave for the night when he came across the women coming in for the night. He had to do a double check because she looked a lot like Joe does but he keeps it to himself and heads out for the night.
The next day Jamie comes into the precinct for his day shift tour with Eddie when he sees the woman again. He stops to say hello to this woman to which she says hi back and heads on her way to work on the streets. But before she could Frank comes in with the undercover officer in charge of her, this was the first time that Frank would meet the young woman since she went undercover for him to take down a huge crime family. They finish up with the meeting and Jamie stops his dad from leaving because he wanted to tell him what he was thinking.
Frank hears Jamie out and invits the officer to meet the rest of the Reagans for the Sunday dinner that night. Jamie stops by Danny's precinct and the lab partner there with a blood sample of the woman. Right before the dinner that night Frank gets the call from Danny saying that the blood matched them, that she was a Reagan.