When a young boy is executed, Intelligence turn to the boy's parents for information and upon further investigation, discover the father has a criminal background and was a part of a local gang. After another shooting in gang territory, this time nonfatal, Lindsay and Halstead speak to the victim's mother to see if the two crimes are related and Mouse works to find a connection. To honor the deceased young victim, Antonio, Platt, Roman, Burguess, Mouse and a number of other CPD officers and members of the community come together for a candlelight vigil.