Why the new Michelle Pfeiffer, Harrison Ford thriller isn't what it seems

”What Lies Beneath” sports a cryptic title and A-list talent Michelle Pfeiffer, Harrison Ford, and ”Forrest Gump” director Robert Zemeckis. So why do the trailers for the film make it look more like a ”Friday the 13th”-style slasher flick than a sophisticated Hitchcockian chiller?

Though early reviews have praised ”What Lies Beneath” for its subtle suspense, TV commercials and theatrical trailers show Pfeiffer not so subtly screaming at a ghost, getting knocked around by Ford, and taking a header off a pier. ”It IS a scary movie,” says Pfeiffer, who plays the movie’s unnerved protagonist. But some viewers are also complaining that the promotional montage reveals too many of the movie’s nail-biting moments. ”The problem is, people want to see everything they’re going to see before they even watch the movie,” says Zemeckis, who worked closely with the film’s U.S. distributor, DreamWorks, to develop the marketing campaign. ”I relate it to McDonald’s. The reason that’s a tremendous success is because people know exactly what they’re going to get. Sadly, we want our lives to be bland.”

Still, the director says that no matter how much the trailer reveals in an effort to sell tickets opening weekend, there are plenty of plot twists left to rattle audiences. The catch is counting on people not to spoil the surprise ending for their friends. (We at EW.com will respectfully refrain from ruining any for you.) ”We live in a world where people need to know everything right away,” says Zemeckis. ”I hope this movie doesn’t become a casualty of that.”

The biggest shock about ”What Lies Beneath” may be that the thrills indicated in the trailer take a backseat in the movie to the complex emotional lives of its main characters, a long-married couple played by Pfeiffer and Ford. As Claire Spencer, Pfeiffer plays a woman who becomes anxious when her teenage daughter (Katharine Towne, late of ”M.Y.O.B.”) leaves for college — and her scientist husband (Ford) is consumed with his research.

Pfeiffer, who has veered away from supernatural chills except for the more-fun-than-spooky 1987 comedy ”The Witches of Eastwick,” says she trusted Zemeckis to guide her away from scream queen territory. ”I was ready for a role that was a real departure, but I was a bit daunted because the thriller was a new genre for me,” says the 43 year old actress, who worked with a scuba instructor to overcome her crippling fear of water before filming the movie’s soggy scenes. ”But I felt like I was in such good hands I felt ready to take the plunge, literally.” After this weekend, she’ll know if ticket buyers are willing to dive in, too.