After Ronnie is injured by Armadillo, Vic and the Strike Team try to take him down before he outplays them, or before Claudette steps on their toes. Meanwhile, Dutch tries to help Danny's career by letting her help in a simple detective case.
- Michael Chiklis as Detective Vic Mackey
- Catherine Dent as Officer Danny Sofer
- Walton Goggins as Detective Shane Vendrell
- Michael Jace as Officer Julien Lowe
- Kenneth Johnson as Detective Curtis Lemansky
- Jay Karnes as Detective Dutch Wagenbach
- Benito Martinez as Captain David Aceveda
- and CCH Pounder as Detective Claudette Wyms
- Lucinda Jenney as Lanie Kellis
- Danny Pino as Armadillo Quintero
- Cathy Cahlin Ryan as Corrine Mackey
- Marguerite MacIntyre as Emma Prince
- David Rees Snell as Detective Ronnie Gardocki
- David Raibon as Van Bro
- Sung Kang as Malcolm Rama
- Michael Sean Tighe as Jarvis Stanley
- Frank Gallegos as Little Pop
- Erick Carrillo as Quazi
- Philippe Bergeron as Nico
- Regina Randolph as Polly
- J. Anthony Pena as Pinto
- Asanio Lara as Mexican
- Christopher Shea as Udel
- Autumn Chiklis as Cassidy Mackey
- Melanie Myers as Officer Paula
- Louis Mendoza as Injured Mexican
- Victor E. Kobayashi as Thai Man
- Kiyoko Yamaguchi as Mrs. Rama
- "If I Ever Leave This World Alive" by Flogging Molly
The term might refer literally to the scar in Armadillo Quintero's face, which is an important element on the events of the season. However, it might also refer to the "emotional scars" left in Corrine Mackey after Claudette Wyms tells her several truths about Vic, or the "scars" shown in Danny Sofer's career and personal life as she loses a promotion and confesses to Vic how lonely she feels, or the "ethnic scars" shown from a long forgotten grudge between the two Thai families: Rama and Kusa.
- International airdates:
- Germany: March 25, 2006
- France: September 5, 2007
- When Danny Sofer almost kisses Dutch Wagenbach, he backs off and says "Kim's making me dinner tonight" which probably means he is still dating Kim Kelner whom he met in Season 1.
- Vic Mackey: I've got a team member in the burn unit, the guy who did it out on the street, and you think now is a good time to screw with my family?
- Claudette Wyms: I think Armadillo went to your house looking for you, Vic. Lucky your wife and kids didn't end up in the burn ward.
- Vic Mackey: My family's off limits.
- Claudette Wyms: You tell that to Armadillo.
- Vic Mackey: I'm telling you!!
- Armadillo Quintero: The first few weeks are the worst. Then the skin gets hard. The stinging goes away.