As networks dither, cable networks rush to fill the vacuum. The Sci-Fi Channel hopes that millions of viewers will devote 20 hours over the next 10 consecutive weeknights watching “Taken” (8 p.m., Sci-Fi), a sweeping 50- year saga concerning four families and several generations deeply affected by alien encounters.

Episode one begins in the waning days of World War II, when Capt. Russell Keys’ plane becomes engulfed in a mysterious blue light. After the war, Keys (Steve Burton) is haunted by visions and learns that all of his fellow crewmen have mysteriously died. Once considered a valiant war hero, Keys abandons his wife and child to become a mysterious drifter in search of the truth about his peculiar encounter. Meanwhile, fanatical Army Capt. Owen Crawford (Joel Gretsch) ruthlessly leads a government program to exploit the wreckage of a crashed saucer near Roswell, N.M. And in Lubbock, Tex., Sally (Catherine Dent, “The Shield”), a lonely widow, becomes intimate with a beguiling stranger who may not be of this world. Tonight’s episode is directed by Tobe Hooper, best known for “The Texas Chainsaw Massacre” and “Poltergeist.”

Tomorrow’s installment takes place in the late 1950s, as the vagabond Keys attempts to spare his son Jesse (James Kirk) from his dreams of alien abduction, and Sally’s otherworldly son earns unwanted attention.

Produced by Steven Spielberg, “Taken” is an often gorgeous-looking piece of filmmaking that employs many of that director’s familiar touches. While the aliens usually appear in a blinding light, these critters don’t seem as benign as “E.T.” or the tuneful visitors from “Close Encounters.” In episode two, aliens lure young Jesse in the guise of a giant storybook squirrel. I had hoped Spielberg would have given up on these cute touches after the scathing reaction to that fabric-softener bear in “A.I.”

Tonight’s other highlights

• Elizabeth Taylor is profiled on a two-hour edition of “Intimate Portraits” (6 p.m., Lifetime).
• A killer uses an earthquake as an alibi on “Monk” (7 p.m., ABC).
• Grandpa Boris and his former rival perform a holiday pageant on “Rugrats Chanukah Special” (7 p.m., Nickelodeon).
• Ray’s warm recollections face painful revision on “Everybody Loves Raymond” (8 p.m., CBS).
• The Oakland Raiders play the New York Jets on “Monday Night Football” (8 p.m., ABC).
• Robson Green (“Touching Evil”) stars as a profiler in the new detective series “Wire in the Blood” (8 p.m., BBC America) based on a series of novels by Val McDermid.
• An actress’s murder trail leads from Boston to the Mojave Desert on “Crossing Jordan” (9 p.m., NBC).

Series notes

Carrie’s busy schedule leaves Doug distracted on “King of Queens” (7 p.m., CBS) … Charged with murder, Harper is pressured to cop a plea on “Boston Public” (7 p.m., Fox) … An awkward morning after on “The Parkers” (7 p.m., UPN) … Mary’s much older boyfriend shocks Eric on “7th Heaven” (7 p.m., WB).

A lesson in honesty on “Yes, Dear” (7:30 p.m., CBS) … Flex revisits his hoop dreams on “One on One” (7:30 p.m. UPN).

A child witness testifies against a killer despite threats against his family on “Third Watch” (8 p.m., NBC) … Hollywood bloopers on “The World’s Funniest Movie Outtakes” (8 p.m., Fox)… Joan recycles her ex-mates on “Girlfriends” (8 p.m., UPN) … Ephram is shocked to see Andy return to his workaholic ways on “Everwood” (8 p.m., WB) … Dee Dee asserts herself on “Half and Half” (8:30 p.m., UPN) … Judy and Bill play games with Linda’s therapist boyfriend on “Still Standing” (8:30 p.m., CBS).