Cold Case is an hour-long crime drama that has aired on the CBS network since 2003. It focuses a Philadelphia Police Department's Homicide squad that investigates murders that have gone unsolved for years, sometimes even decades.
The series focuses largely on Detective Lilly Rush (Kathryn Morris) who was (until the third season) the squad's only female Homicide detective. Initially paired with Detective Chris Lassing (Justin Chambers) for the first few episiodes, her long-term partner has been Detective Scotty Valens (Danny Pino). The squad is commanded by Lieutenant John Stillman (John Finn) and includes Detectives Nick Vera (Jeremy Ratchford), Will Jeffries (Thom Barry), and, starting in the third season, Josie Sutton (Sarah Brown), who was replaced after a few episodes with Kat Miller (Tracie Thoms).
Structure
Episodes typically begin with a flashback to a point several years earlier where the victim, and often other characters, are introduced and their situation is established. From there, the scene fades to sometime later, when the victim's body is shown with no one else present.
A contemporary police officer is usually shown filing a box of files pertaining to the unsolved case among several other boxes. In cases, where the body was never found the scene might show a Missing Persons report. The scene might also show a medical examiner's report if the death was thought to be an accident or suicide.
From there, the story shifts to the present, where new evidence (such as a newly discovered body, or new information from a witness) prompts the detectives to re-open the case.
Acquaintances of the victim are interviewed by detectives and recall their experiences with the victim which is then seen in flashbacks. Witness are often portayed by two guest actors: a younger one to appear in flashbacks when the victim was alive, and an older one to portray the character as they appear in the present (though some actors portray both versions of the character, depending on their age and if the case was recent enough).
Flashbacks typically employ popular music contemporary to the era and are shot in a way that is distinctly different visually from the scenes in the present. When the flashbacks are all viewed, the victim is usually shown having gone through some sort of character arc. When the killer's identity is revealed and confronted, their confession is shown through one final flashback revealing the circumstances of the victim's death.
The episode then ends with no dialogue, but rather one more piece of period music plays over a montage in which the killer is arrested; other witnesses are shown going on with their lives (both intercutting between their younger and older selves); one of the detectives is shown stacking the case box back with the other boxes, now with the word 'CLOSED' written on the lid; finally, one of the detectives (usually Lilly) or someone else close to the victim is shown seeing them apparently alive, well, and happy for just a moment, before they fade away, as though to suggest the victim can "move on", now that their murder has been solved. Since the show doesn't delve into the supernatural, it's generally assumed the victim's appearance at the end is more a figment of the other person's imagination.
Whether or not the show can be called a "procedural" is debatable. The show does not delve into the personal lives as much as some, such as NYPD Blue, but still more than others, such as Law & Order. Love interests for one character have sometimes been shown over several episode, and occasionally subplots onvolving a detective's personal life is shown, though invariably, the case shown in the episode takes precendence.