Supernatural is an American paranormal/horror show based around a Monster of the Week structure topped off with an over-reaching arc, while simultaneously retaining humor through various means of Leaning on the Fourth Wall. It follows Dean (Jensen Ackles) and Sam Winchester (Jared Padalecki), two brothers who hunt creatures based on Urban Legends, Classical Mythology, and Abrahamic theology.
The first season featured the brothers searching for their missing father, but, for the most part, the series features them Walking the Earth as they travel from town to town in search of supernatural problems to solve. Though the Big Bads get bigger each season, it's more common that Dean and Sam already have their hands full with each other. It uses a diverse score of classic rock songs that feature heavily throughout, to encapsulate the gritty rock-and-roll life they lead, and features Dean's 1967 Chevy Impala as almost another character.
Other main characters include Bobby Singer (Jim Beaver), father figure and Knowledge Broker to the main characters, Castiel (Misha Collins), an angel that enters in the fourth season, and Crowley (Mark Sheppard), a demon introduced in the fifth season who later becomes the King of Hell. More information about them, as well as the show's stable of recurring characters, can be found on the character sheet.
Famous for three main things:
- The Cast Full of Pretty Boys.
- The sheer amount of Mood Whiplash.
- How it raised torturing its two leads (emotionally and physically) to a fetishistic art-form. Not that it doesn't torture other characters on a regular basis.
A Spin-Off Web Original titled Ghostfacers, centered around a pair of minor recurring characters, was launched during Season Five in conjunction with the show's 100th episode. A prequel to the series (in comic form) entitled Supernatural: Origins was released by DC Comics in 2009. There's a total of six issues. Madhouse made an anime adaptation, the animation for which can be seen in this trailer. The American release of the first season of the anime came out on July 26, 2011.
The show itself is in its thirteenth of its originally-planned five seasons, with executive producers Robert Singer and Andrew Dabb as the current showrunners. This responsibility previously fell on creator Eric Kripke for seasons 1 through 5, Sera Gamble for seasons 6 and 7, and Jeremy Carver for seasons 8 through 11.
A proposed spin-off show, entitled Supernatural: Bloodlines intended to explore both hunter and monster families in the show's universe, aired an extremely Poorly Disguised Pilot late in the ninth season. It was not picked up by the CW for full production. Another potential spin-off 'Wayward Sisters' focusing on recurring women from the franchise aired a Poorly Disguised Pilot in the 13th season. It too was not picked up.
There is an in-progress recap page here. Tropes for individual episodes are listed there.