When District 21 goes after a Colombian drug gang following a series of brutal slayings, an asset in the investigation emerges.
- Big Bad Wannabe: The first victim, Rev, was described as some wannabe drug dealer by Voight's informant Maurice Owens.
- Big Eater: Coop’s house is littered with pizza boxes and Chinese take-out containers.
- Bound and Gagged: Rev before being beheaded.
- Decapitation Presentation: Coop's head is mounted on his kitchen counter when Intelligence raids his house.
- Establishing Character Moment: The Cold Open features Voight taking a drug dealer outside the city limits, beating him up, forces him to give up his supplier, takes his money, threatens the dealer that he will kill him should he ever return to Chicago, and gives him some money for a bus fare.
- Gory Discretion Shot: We only see the aftermath of the beheadings.
- I Have Your Wife: The cartel kidnaps Antonio's son, Diego.
- Killed Offscreen: Coop and Shane Cameron, who was shot in the chest rather than beheaded like Coop.
- Machete Mayhem: Pulpo's choice of weapon is a machete.
- New Meat: Olinsky pulls Ruzek from the academy to join Intelligence.
- Off with His Head!: Pulpo beheads his victims with a machete.
- Only Known by Their Nickname: Eric Cooper was referred as Coop.
- Poor Communication Kills: Intelligence Sergeant Voight clashes with Violent Crimes Lieutenant Belden. They don't share information. When Intelligence rolls up to a house belonging to a drug dealer, Violent Crimes is there as well. Intelligence Detective Willhite ends up shot and killed.
- Posthumous Character: Eric Cooper, or better known as his nickname Coop, is never physically seen until Intelligence discovers him beheaded in his house.
- Spiteful Spit: Pulpo does this when Antonio shows him the blood of Detective Willhite on the latter's hand. This causes Antonio to lunge at Pulpo until he is Dragged by the Collar by Halstead and Ruzek.
- The Aggressive Drug Dealer: Averted. Rev and Coop weren't hostile, but the drugs they were selling were killing people.
- The Cameo: Gabriela Dawson (Antonio's little sister) and Leslie Shay from Chicago Fire are the responding paramedics after Willhite gets shot.
- The Dreaded: Pulpo.
