Blue Bloods Season 12 Episode 20 revolves around big changes.

Danny and Baez try to save a woman who is supposed to be in witness protection and is being threatened, but the woman's house is bombed and she is blown up. The doctors can't save her, but are able to save her baby. Baez wonders whether they are really making any difference, since the perp keeps getting arrested and released and doing worse things.

Meanwhile, Eddie runs into a similar issue after a perp who is robbing people at knifepoint is released because the DA's office refuses to prosecute what they see as a minor crime. The guy returns to the store and gets into another fight with a patron, this time stabbing her. Eddie's partner ends up shooting him.

Danny's case overlaps with Jamie and Joe's, as they have a suspect in common. Danny initially insists this is his case, but then agrees to work with his brothers.

Finally, Erin finds herself in the middle between Frank and her boss after Frank has a press conference criticizing new DA office policies about refusing to prosecute non-violent offenders.

To find out what happens, watch Blue Bloods Season 12 Episode 20 online.