Threshold is an American science fiction drama television series that ran on CBS from September 16 to November 22, 2005.

The remaining episodes were aired on Sky1, a channel in the United Kingdom owned by Sky, who co-produced the series with CBS.

The series stars Carla Gugino as Dr. Molly Caffrey, a high-level government crisis management consultant from the Blackwood Institute whose job is to create contingency plans for use in emergencies ranging from natural disasters to nuclear war.

In order to have "all bases covered", one of her plans, code-named Threshold, is developed for dealing with the unlikely eventuality of first contact with aliens.

Caffrey's Threshold plan calls for the formation of a secret government task force known as the Red Team.

As a result, several top scientists are seconded: Dr. Nigel Fenway (Brent Spiner), an individualistic NASA-employed microbiologist; Lucas Pegg (Rob Benedict), a somewhat unsure-of-himself aerospace engineer on the eve of his marriage, and Arthur Ramsey (Peter Dinklage), a mathematics and linguistics genius with a penchant for unpredictability, alcohol and women.

Baylock (Charles S. Dutton), while freelance paramilitary operative Sean Cavennaugh (Brian Van Holt) serves as the "muscle" of the group (and apparent potential love interest for Caffrey).

An ongoing subplot of the series is the emotional impact Threshold has on Caffrey herself, as she is required to make life-and-death decisions on an almost daily basis.

Prior to Threshold's cancellation Brannon Braga announced that Catherine Bell would be joining the series, as would another actress, Jacqueline Kim, who would appear as Lucas's wife Rachel.

[2] In the unaired episode "Outbreak", Bell guest stars as Dr. Daphne Larson, a botanist brought in to examine the mutated vegetables from "Revelations".

According to writer Brannon Braga on the 2006 DVD release, word that production of the series was being terminated was received midway through shooting of the episode "Alienville".

In the series, four variants were discovered to occur in humans who were exposed to the signal including: In Episode 11, which was unaired in the US, one of the hybrids reveals that the aliens plan to save humankind by changing their DNA and the surface of the earth.

This is because millennia ago, far out in space, two neutron stars collided, creating a gamma ray burst - the radiation of which is heading for Earth and will, when it arrives in six years, end all life on the surface of the planet.

The text of that letter is below: Dear Dr. Molly Anne Cafrey In reply to your request for information at the following coordinates Eight hours right ascension, thirty four degrees south declination It has been confirmed that approximately 400,000 years ago two neutron stars collided at these coordinates, and the cosmic radiation that resulted from this collision is expected to affect the Earth in approximately six years.

[4]A featurette included on the August 2006 DVD release of the series confirmed a number of reported and rumored storylines that were planned had the series survived: The episodes that were not aired by CBS also included several plot elements that would probably have been explored had the series continued: for example, Dr. Sloan, the so-called "Vigilante" introduced in the episode of the same name, whose self-appointed mission is to kill infectees (the episode also indicates a romantic attraction between him and Caffrey); the real nature of the gamma ray burst headed for Earth indicated in "The Crossing"; the effect of Threshold on Lucas Peggs' marriage; Cavennaugh's search for his brother (who becomes infected and provides the aliens with information about Threshold); the development of an alien infectee culture (who refer to themselves as "improved" humans) and their perception that the US government is persecuting them (an element introduced in the final episode, "Alienville"); and the aftermath of Caffrey's orders to increase Threshold's powers in "Outbreak".

Threshold was the first CBS television series to utilize "streaming video" to re-air new episodes after the original airdate.

The following television season (2006–07) CBS incorporated this concept into a streaming video area on their website called Innertube.

The best came from USA Today, who say "Convincingly smart, realistically unsettled and sexy as all get-out, Gugino radiates so much TV star power, it just might be visible from outer space."