Blue Bloods Season 10 Episode 18 revolves around what it means to uphold the law.

When Frank's friend the Monsignor asks him to look into an accusation that has been made against a priest, Frank discovers that the priest is no pedophile -- but he is a father. he priest has an 11-year-old son, and the boy's mother works as his assistant. The monsignor says in that case, the priest must be removed from this parish.

Frank talks to the priest and then tries to convince the monsignor not to do this, but the monsignor says he must uphold God's law and can't look the other way.

Meanwhile, Danny and Baez investigate the deaths of two models who OD'd on a designer drug. When three more people die, they become determined to catch the dealer. However, when they find out that the woman in charge of the models bought the drugs, they arrive at her home too late and find she has hung herself.

Finally, Jamie and Eddie investigate a robbery and discover a social worker who worked in the store is behind it, while Erin butts heads with an overeager new ADA who messes up a case by talking to the press.

To find out what happens, watch Blue Bloods Season 10 Episode 18 online.