STRETCH a slasher flick concept across 13 hour-long episodes and you get the new murder mystery series “Harper’s Island.”

The body count rises weekly, as a murderer stalks visitors of the picturesque island situated off the coast of Seattle. These guests are about to attend the wedding of Henry Dunn and Trish Wellington (Christopher Gorham and Katie Cassidy), most of them unaware of the grisly crimes single-handedly committed by a madman who visited the place seven years ago.

But some of them do know that dark chapter in the island’s history. Among the guests is Abby Mills (Elaine Cassidy), the groom-to-be’s best friend. She’s a former resident of Harper’s Island whose mother was among the rampaging killer’s victims. The murderer was gunned down by Abby’s Sheriff father (Jim Beaver).

But there’s a baffling new series of killings being committed by a mysterious assailant.

Just like the ’90s “Scream” movie series, most of the characters in “Harper’s Island” are easily distinct, falling into almost archetypal categories. There’s the good girl, the outsider, the old flame, and so on. When the slayings start, however, everyone becomes a suspect, and many of the characters are fleshed out just enough to reveal some possible motives. Figuring out the real deal in a gaggle of red herrings can be tough and challenging.

The slasher-murder mystery works, the whodunit puzzles a bit reminiscent of those in much smarter shows like “Twin Peaks” and “Veronica Mars.” And like in the aforementioned “Scream,” established facts aren’t always reliable, and there are untold secrets that will make sense of the chaos in due time.

The pacing can be frustrating, initially, since it takes a few episodes for the characters to discover the terrible things happening around them. Also, there are transparent horror clichés and obvious ploys that don’t work too well.

But the payoff is worth the wait. Many questions are answered satisfyingly, sometimes shockingly. The revelations elaborate on the entire horrid affair, but it takes patience –and plenty of casualties – to get to some twisted truths.

“Harper’s Island” airs on Studio 23 every Wednesday at 9 p.m.

Kuya Germs’ humble beginnings

Tonight on “I-witness,” Sandra Aguinaldo presents the life of German Moreno through the eyes of his long-time friends and Philippine entertainment legends Dolphy, Gloria Romero and Pilita Corrales.

They recount the colorful story of Kuya Germs, from his humble beginnings as a theater curtain-puller during the 1960s to his heydays as star discoverer.

The episode airs at midnight after the late night newscast “Saksi” on GMA 7.

Moms show premiere

Q Channel 11’s “Full Time Moms,” which airs Mondays to Fridays, premieres today at 7:30 p.m., with hosts Suzi Entrata-Abrera and Christine Jacob-Sandejas chatting with the all-girl trio La Divas.

Known individually as Jonalyn, Aicel and Maricris, the girls talk about their journey to success and the all-out support of their parents. Also in the show are comedians Tess Bomb and Buboy Ipus who will teach moms about being stage mothers.

High definition programs

SKYCable announces some of the programs on its two channels in high definition –History HDTM and Discovery HD.

“San Quentin Film School,” a Prison Project tracking a group of inmates at California’s San Quentin State Prison, airs Tuesdays at 7 p.m. on Discovery Channel.

The channel also features “Mighty Ships,” an exploration of everything above and below the deck, on Fridays at 6 p.m.

On the History Channel, the truths and myths behind the world of epic heroes and villains are unveiled in “Battles B.C.,” which premieres October 27 and airs every Tuesdays at 9 p.m.

Sonny in Hollywood

On Disney Channel’s “Sonny With A Chance,” Sonny Munroe (Demi Lovato) is discovered by a television producer and gets the chance to star in the most popular sketch comedy series for kids and tweens.

The series premieres on October 17 at 9:30 p.m. and airs Saturdays and Sundays at 9:30 p.m.