Sci-Fi shows stack Fall TV lineup

Say goodbye to summer and hello to a fall TV lineup aimed to please sci-fi fans.

The major networks are taking viewers everywhere from alternate universes to the vast corners of the human mind.

Executive producer Marc Guggenheim tells Popular Mechanics that Flash Forward hopes to hook fans of Grey's Anatomy and Lost. This 13-episode ABC series has an anxiety-rich premise: every person on Earth blacks out simultaneously, for two minutes and 17 seconds. But they remember something. Their destiny? (Sept. 24, 8 p.m., ABC)

Lost returns for season six. Actor Josh Holloway, who plays Sawyer, promises this seasons will pull it all together, reveal the mystery and "the material will finally make sense." (2010, ABC.)

The last time the Visitors appeared was in the 1983 miniseries. Now they return in "V," seeking some of Earth's natural resources, vital to their return home. If we help them, they will share their technology. But there may be a catch. (November 3, 8 p.m., ABC)

FBI agent Olivia Dunham explores an alternate universe in the second season of Fringe. President John F. Kennedy was never assassinated, and there were no memorable events on Sept. 11, 2001. Startling revelations are promised. (September 17, 9 p.m., FOX)

More memory-erasures and drama in the expanding universe of Josh Whedon's Friday night series, Dollhouse. Popular Mechanics describes Dollhouse as "Charlie's Angels" meets "The Matrix." (September 25, 9 p.m., FOX)

The X-Men aren't the only mutants among us. Heroes returns with superheroes who face human hostility as well as their own angst at being ... different. New "heroes" include a tattooed woman, a time traveler, and a knife thrower you may recognize as Darth Maul. (September 21, 8 p.m., NBC)

For more information on the Fall TV lineup, click here.