When Lindsay is tipped off about a grieving father looking to avenge his daughter's death, Olinsky goes undercover as a hitman-for-hire. With Gang Intelligence lacking enough evidence to arrest the original gang-banger in question, the team works to reinvestigate the case. Ruzek comes back after finishing his undercover assignment only to have Voight knock him down to patrol duty.
Season 4 Episode 15 of Chicago PD was watched by 6,680,000 viewers, resulting in a 1.30 rating in the 18-49 demographic.
District 21 of the Chicago Police Department is made up of two distinctly different groups: The uniformed cops who patrol the beat and deal with street crimes, and the intelligence unit, the team that combats the city's major offenses, such as organized crime, drug trafficking and high-profile murders. Leading the intelligence team is Sgt. Hank Voight, a man not against skirting the law in the pursuit of justice.
Demanding and tough, only those who can take the heat survive under Voight's command. Take Det. Antonio Dawson, for example. Despite a troubled history with his boss, Dawson has ambitions of running the unit. If that means facing off against Voight every day, he'll persevere. From the street cops with dreams of moving up to the elite crew who are already in, life on the job is a daily challenge.