An undercover operation is underway to trace a drug pipeline. Two detectives get shot, killing one. Danny investigates along with the entire police force, out to avenge the killing. Nicky and Henry dance and sing in a show.

Jamie saves a baby from an apartment fire but Renzulli gets the credit so that his cover remains intact. A fireman's 11-year-old son, a school friend of Danny's son, feels that his father did not commit suicide. Danny investigates.

Danny and Jamie are playing basketball with some other guys. A guy Danny knows gets into it with a guy Jamie knows; the guy Danhy knows smacks the guy Jamie knows. The one who was smacked has to be hospitalized and he demands that the one who smacked him be arrested and Danny reluctantly does it. He tells the guy he knows that his sister is the D.A. and maybe he can talk to her. Erin is approached by a man who asks her to re investigate his daughter's unsolved murder which is 15 years old. Erin goes to Danny and asks him to look into the man's daughter's murder. It seems the man thinks that his daughter's boyfriend who's the son of a wealthy man should be considered. Danny agrees, if she helps his friend. Danny goes to see the detective who investigated the murder and he tells Danny that he had an alibi and took a polygraph and passed. Erin informs Danny that his friend has a previous record which means he has to be indicted. Jamie offers to talk to the guy he knows. Erin and Danny see the man and tell them what they learned. He tells them that the guy's father's company has polygraph which he could have learned how to beat it. And he also tells them that his alibi witness was a friend. So Danny decides to look deeper. Frank and Garrett have a disagreement when Frank is interviewed and a very touchy question is asked.

Frank battles City Council speaker Regina Thomas over protests against police brutality; Jamie and his nephew, Joe Hill, try to locate a missing Danny and Baez; Eddie helps an abrasive woman find her father's body.