The evolution of television and soap operas continues. The old daytime serials may have gone the way of “Guiding Light,” but they’re finding new places to attract viewers, particularly younger ones. Nickelodeon has experimented with nightly soaps, including the supernaturally inclined “House of Anubis” and the music-business melodrama “Hollywood Heights.”

Beginning tonight, YouTube launches its first scripted series, “Runaways,” available on the website’s “AwesomenessTV” channel. It’s a tale of murder and mystery at a posh prep school. The prettiest and most popular couple has gone missing on the very day that another student was found murdered. Are they also victims? Will they be implicated in the crime? Are they merely on the lam for romantic reasons?

YouTube will make another 35-minute episode of “Runaways” available every day over the next seven days. The series features the kind of performances you would expect from model-perfect teens all decked out in prep school suits and ties. It claims to be “Pretty Little Liars” meets “Gossip Girl,” but it reminds me of every other show that’s been on the WB and CW since “Dawson’s Creek” debuted in 1998, roughly the same time when most of the intended audience for “Runaways” was born.

”Runaways” was created by Brian Robbins and Joe Davola, whose credits include “Smallville “and “One Tree Hill.” It’s clearly a television show for people who no longer watch television. At least on television.

• Fans of more traditional teen tantrums can return to “Mean Girls” (6 p.m. and 8 p.m., ABC Family). “Girls” features an engaging performance from Lindsay Lohan that reminds us of what she was capable of before getting lost in a parallel tabloid dimension.

Tonight’s other highlights

• U.S. Open Tennis continues (6 p.m., ESPN 2).

• A male would-be singer has a Cinder-fella story come true in the 2012 musical “Rags” (7 p.m., Nickelodeon).

• “Dark Secrets of the Lusitania” (8 p.m., National Geographic) recalls the sinking of the passenger liner by a German submarine in 1915.

• Kane finds it hard to control his feelings for his new aide on “Boss” (8 p.m., Starz).

• “Deadly Women” (9 p.m., ID) profiles killers inspired by greed.