Blue Bloods Season 11 Episode 15 features the long-awaited return of Joe Hill.

When Danny and Baez find out about a murder victim's involvement in buying illegal guns, they rush to the scene... and find an undercover Joe among the troublemakers.

Danny is peeved to find out that Jamie and Frank knew and didn't tell him. What if he'd hurt Joe or killed him because he didn't know? His discontent with this keeps growing, to the point that he's barely talking to his family at Sunday dinner. Frank tells him to go ahead and tell everyone the truth. Eddie and Erin are shocked and Eddie is also upset that nobody told her. Frank says if Jamie could have, he would, and this is how it works. He storms off.

Meanwhile, Joe could be in trouble, as mob boss Kenny suspects he is a cop and calls Jamie while holding him at gunpoint. Kenny is mollified for now, but Jamie worries that Joe's cover has been blown thanks to Danny's operation.

Jamie meets up with Joe and tells him he's pulling him off the assignment but Joe wants to finish out a sting first. But the bad guys are onto him and manage to lose the cops watching him.

To find out what happens, watch Blue Bloods Season 11 Episode 15 online.