SAN DIEGO • The film was scary, but that was not why people at a sneak peek screening of a new horror movie called The Woods last Friday were screaming: In a master stroke of stunt marketing, it turned out that The Woods was not The Woods at all, but a top-secret Lionsgate sequel to The Blair Witch Project.

There is nothing unusual about a studio trying to dust off an old franchise. But Lionsgate's tactics in this instance were unorthodox. It is betting that the payoff will come at the box office in September, with moviegoers drawn to the film because it feels both new and nostalgic - in other words, not just another tired sequel.

For two years, Lionsgate had referred to the movie as The Woods. Actors were given fake scripts at auditions. Everyone working on the film had to sign a nondisclosure agreement. Then, Lionsgate mounted a fake marketing campaign, with posters, a trailer and a booth at Comic-Con for The Woods.

And there was the sneak peek screening at a San Diego theatre. As the movie began to play last Friday, Lionsgate switched the fake campaign for the real one. It released a new trailer online, changed the film's page on the Internet Movie Database, made over its Comic-Con booth and unveiled a new website.

Horror bloggers, who were briefed on the secret early, posted euphoric news items in lockstep. The sequel, titled simply Blair Witch, began trending worldwide on Twitter. Directed by Adam Wingard, the new film is set in the Maryland woods and follows the younger brother of one of the murdered campers from The Blair Witch Project (1999).

NEW YORK TIMES