Sanctuary was originally an eight-webisode series which SyFy purchased the rights for after the series was successful. It is about a worldwide network of Sanctuaries, places which deal with beings known as Abnormals, some of which look human, or mostly human or human for most of the time, but others are very definitely not. Deal with does not mean kill; the Sanctuaries are intended to provide a safe haven for the Abnormals from the normal world. Even though some of the Abnormals are very dangerous; it is normal people who will come off worse in an encounter, at least on an individual basis.
The series is based around one particular Sanctuary, run by the very long-lived Dr. Helen Magnus. Magnus is also the head of the global Sanctuary Network. There are a few main characters and a number of recurring ones. The Sanctuaries also have access to advanced, and often extremely experimental, technology – much is designed by Henry, who works for Magnus. The series starts when Dr. Will Zimmerman, a former FBI agent and psychologist, stumbles across an Abnormal during a police case. Magnus offers him a new job rather than the one he currently has with the police. The Sanctuary in question is a very large castle-like building that looks like it was shipped piece-by-piece from another country (it’s not specified where it is based, but the Sanctuary looks Old World and the city New).
Sanctuary was filmed on a very low budget which resulted in many episodes lacking at least some of the main cast and a lot of use of green screen technology. Often, the only real things on screen are the cast and anything they directly touch. Even rooms such as offices that were regularly used were not actually there. This is actually not that noticeable, as the CGI works surprisingly well. Sanctuary was also noted for good writing – it could be compared to such as classic Tom Baker Doctor Who; little budget but decent scripts.
Episodes, especially the earlier ones, often revolve around dealing with a specific problematic Abnormal, but there are many multi-episode arcs as well, both of immediately connected episodes and background stories that eventually develop into main ones, with a few major foes over the series. With Abnormals having unusual abilities, these abilities are often either feared or desired, so the Sanctuary Network is often not the only organisation involved. They tend to be the organisation with the best intentions though.
The series has quite a lot of connections to Stargate, the primary one being, of course, Amanda Tapping (Sam Carter). Additionally, Sanctuary‘s creator, Damian Kindler, wrote for Stargate SG-1 and Stargate: Atlantis, and Christopher Heyerdahl from SGA (primarily as Todd the Wraith) has two major roles (one with a lot of prosthetics, one with none) and there were lots of guest stars: Michael Shanks (Daniel Jackson), Paul McGillion (Dr. Carson Beckett), Gary Jones (Walter/Chevron Guy), Caroline Cave (two minor roles) and Tom McBeath (Harry Maybourne).
Sanctuary ran for four seasons, with season three having twenty episodes, and a mid-season finale, rather than the usual thirteen.