Construction workers discover a skull with a bullet hole under the ruins of a disco club that burned down in 1978. 22 people died in the fire. Rush and Valens come to the conclusion that the burning of the club was arson, meant to cover up a murder leaving them with not one, but 23 cold cases.
- Kathryn Morris as Lilly Rush
- Danny Pino as Scotty Valens
- John Finn as John Stillman
- Jeremy Ratchford as Nick Vera
- Thom Barry as Will Jeffries
- Josh Hopkins as ADA Jason Kite
- Conor Dubin as Benny Rosen
- Amanda Wyss as Sonya Witkowski (2004)
- Robin Riker as Doreen Denova (2004)
- Robert Cicchini as Paul Chaney (2004)
- Michael Fairman as David Rosen (2004)
- Nichole Hiltz as Doreen Denova (1978)
- Ciara Hughes as Sonya Witkowski (1978)
- Lorna Raver as Myra Rosen (2004)
- Justin Meloni as Paul Chaney (1978)
- Robert Maffia as David Rosen (1978)
- Rick Foster as Mark Rigley
- Johnny Palermo as Ken Mazzacone (1978)
- Ameenah Kaplan as Leticia Castillo
- Mala Wright as Market Shopper
- Joey Diaz as Ken Mazzacone (2004)
- Unknown Actress as Myra Rosen (1978)
- This episode was partly inspired by the events surrounding the Station nightclub fire in 2003.
- This case features 23 homicides, the most for a single case in the series.
- The Trammps "Disco Inferno"
- Earth Wind and Fire "After the Love is Gone"
- ABBA "Dancing Queen"
- Gloria Gaynor "I Will Survive"
- Alicia Bridges "I Love the Nightlife"
- Chic "Le Freak"
- Bee Gees "Stayin' Alive"
- Closing Song: Donna Summer "Last Dance"