Blue Bloods Season 12 Episode 13 is about mistaken impressions.

When a friend and mentee of Henry's dies suddenly, Henry is convinced there was foul play. He doesn't understand how a fit, healthy man could have fallen and hit his head.

Jamie has his doubts but agrees to look into it, especially when Henry points out that an ex-mobster named Chris Kelly was released from jail just before Harold's death. But when Jamie looks into it, Kelly claims that Harold saved his life and that he would never hurt him.

Meanwhile, Erin is suspicious when she sees Anthony with a young Eastern European girl. She investigates the girl's background and follows them to a nearby bar. Anthony tells her that the girl is the daughter of a mobster he arrested. He checks in on her periodically to make sure she's okay. He also tells Erin to mind her own business and that he needs space from her.

Finally, Danny helps Frank investigate whether a cop who was recently injured on the job was dirty, but th need to look into this puts Frank at odds with the victim's wife.

To find out what happens, watch Blue Bloods Season 12 Episode 13 online.