Jared Padalecki and Jensen Ackles Jared Padalecki and Jensen Ackles

I remember this one time, when I was baby-sitting for a couple down the street, I started getting these scary phone calls. I reported the calls to the phone company and they told me they were originating from inside the very house! What, you don't believe me? OK, did I ever tell you about the time an escaped mental patient came at me and my date with his hooked hand? WB's Supernatural, premiering tonight at 9 pm/ET, takes its lead from such urban legends and adds a whole lot of scariness, as brothers Dean and Sam Winchester — played by Jensen Ackles (Smallville) and Jared Padalecki (Gilmore Girls) — face down all manner of American folklore frightmongers while searching both for their MIA dad and the truth about what (and I do mean what) killed their mother some 20 years ago.

Much has been said and written this season about the many new "supernatural"-themed offerings in prime time, but WB's contribution shouldn't be Lost in the mix. Sure, it begs questions about who and what and why and how, and yes, it has an ongoing mythology, but this debut's mission is to deliver big-screen-caliber horror. "This is the show that's designed to make it difficult for you to go to sleep at night after you watch it," boasts McG, the director of the Charlie's Angels movies and an executive producer on Supernatural. "If you're watching it by yourself, you're in trouble, because you're going to be looking behind the door and your mind is going to be playing tricks on you." Providing such peek-through-your-fingers fare, McG smiles, "is a delicious feeling."

Of course, being on broadcast TV, Supernatural can't get too supergory. "We're not afraid of showing some blood, if it has the greatest effect for the audience," says executive producer Eric Kripke, who spent eight years trying to sell the series' concept. "But we're quite impressed and visually inspired by all of the great horror coming out of Japan, which is so evocative and subtle and sophisticated. We're interested in capturing that."

Indeed, the premiere outing — in which the Winchester boys wage war on "the weeping woman" (you know, the lady who drowned her kids and then killed herself, only to linger on and haunt others as a malevolent ghost) — features frightfully good special effects throughout and has a murky atmosphere that is almost palpable. "Part of the promise that we made [to the actors] was that the show would feel like a movie every single week," says McG. "We're going to fight as hard as we have to fight to make sure that is protected. We don't want to let the wheels come off as we get into the season and let the scares feel small."

Just what kind of scares lie ahead? Expect a veritable Who's Who of childhood sleepover ghost-storytelling. "As the boys investigate and chase the demons, creatures and spirits from urban legends and American folklore, they fairly quickly come across the Hook Man, and Bloody Mary," Kripke promises, "and there will be doppelgängers and succubi.

"The writers sort of have a mandate that the show must be extremely Google-worthy," Kripke adds. "Even the throwaway references in the pilot —  the poltergeist in Amherst, the devil gates in Clifton — have a basis in real life. There is so much rich stuff out there, we would be remiss in avoiding it. Everything we're touching upon can be found in true-life folklore."

Sounds good — except does that mean an episode about a guy coming home from Tijuana with a strange little stray dog (à la the famous "Mexican water rat" yarn) is in the works? "Obviously, we have to be scary first and foremost," answers Kripke. "Every week, our promise to the audience is that we're going to scare the living hell out of you. Can we have quirkier episodes as the seasons progress? Sure. But for now, it's a stripped-down, badass-scary show."