A "Knockout Game" let to a pregnant woman being assaulted and losing her unborn child. As Danny and Baez tracked down the assailants, Danny inadvertently tells the woman's husband the suspects name.

The next day, Moses Caldwell was dead and Danny had to decide whether to pursue a suspect who was already grieving the loss of his child.

In the end, Danny made the arrest but the grand jury chose not to indict.

Meanwhile, on Blue Bloods Season 4 Episode 17 Frank had to choose whether to promote an officer who was the son of a good friend of Henry's. Was the promotion because of who he knew, or was it really deserved? Garrett helped Frank see that Timothy had earned the promotion, no matter what his connections.

And Erin unceremoniously ended her fling with her ex, much to his dismay.

Watch Blue Bloods online here at TV Fanatic.