Perry Mason is best known to most people (including myself), through the 1950s/60s television program. I have heard that the original stories were more nuanced, but the show is known for having a formulaic structure, with a melodramatic ending. The typical Perry Mason story could be broken down into four parts, each roughly a quarter-hour long:

  1. The introduction: Someone, usually a fairly middle American person, sees a legal problem on the horizon, and consults with Perry Mason over it. This problem often involves gambling debts, blackmail, love affairs, or something else that is nefarious but still non violent. This usually also introduces us to a group of characters who will become suspects. This usually takes place in Los Angeles, although sometimes Perry Mason is on vacation to another town.
  2. The crime: One of the players is murdered, and Lieutenant Tragg (apparently the only homicide detective in LA) shows up and arrests Perry's client.
  3. Usually around the half-hour mark, the trial (actually a type of Grand Jury hearing) begins. The first half of the trial usually has mounting tension, as Hamilton Burger and Lt. Tragg seem to prove an almost airtight case against Perry, until:
  4. The trial, concluded: sometimes with a phone call to Paul Drake, and sometimes with a brief trip to gather new evidence, Perry finds a way to save his client. He does this by questioning someone in the courtroom until someone, either a witness or a spectator, stands up and confesses. The show then has a brief denouement where Perry, Paul and Della reveal how they realized the true criminal.

As mentioned, this is rather formulaic and improbable: most murder trials don't end with a confession. However, given the technical limitations of television at the time, and the need to fit every program into around 50 minutes, it is probably a necessary break from reality. The first half of the program, where Mason questions his client and provides legal advice, usually comes across as quite realistic compared to the dramatic endings. Also, within the formula, there is quite a bit of diversity in Perry Mason stories: some are tension action stories, others are soap operas, and some are vaguely farcical.

Someone watching Perry Mason will know what they are getting, but that isn't always a bad thing.