The SCI FI Channel's "Sanctuary" stars Amanda Tapping, already known to fans from "Stargate SG-1," as Dr. Helen Magnus -- a scientist who holds the secrets of a group of strange and terrifying beings that hide among humans.  Along with forensic psychiatrist Dr. Will Zimmerman (Robin Dunne), tech wiz Henry (Ryan Robbins), and her daughter Ashley (Emilie Ullerup), Magnus protects this threatened phenomena.  The mysterious John Druitt (Christopher Heyerdahl) also lurks. "Sanctuary" is the first series to use mostly virtual sets shot on green screen.

CBS show "The Unit" follows Special Forces operatives around the globe as they take on dangerous undercover missions. Dennis Haysbert as Jonas Blane leads the unit, which includes new recruit Bob Brown (Scott Foley), Colonel Tom Ryan (Robert Patrick), Mack Gerhardt (Max Martini) and Charles Grey (Michael Irby).

"Terminator: The Sarah Connor Chronicles," the continuation of the apocalpytic Terminator storyline, follows Sarah and John Connor as they try to survive constant assassination attempts and living with the burden of saving humanity on their shoulders, all with the help of another robotic killing machine in the form of a young woman.  Lena Headey, Thomas Dekker, Summer Glau and Richard T. Jones star.

"Dexter" is a Showtime program featuring Michael C. Hall as a 'good' serial killer and blood spatter expert.   The drama series is based on the novel "Darkly Dreaming Dexter" by Jeff Lindsay and opens its third season on September 28.  The Emmy-nominated show also co-stars Julie Benz, Jennifer Carpenter, Lauren Velez and more.