Season 4 Episode 21 episode 21

Blue Bloods Season 4 Episode 21 “Above and Beyond” Photos

Blue Bloods Season 4 Episode 21 “Above and Beyond” Photos

bb_abovebeyond2When a detective from Danny’s precinct is killed while working undercover, Frank puts on a full-court press to find his killer, only to discover that the deceased had a big secret.

RELATED | Blue Bloods Season 4 Episode 21 “Above and Beyond” Guide

Check out the sneak peek images for "Above and Beyond" (airing on May 2) in the gallery below:

Source: CBS