(Business 2.0) – It began as a Web-based mystery. Who hacked the website of a Napa Valley beekeeper, leaving behind a series of GPS coordinates? Why were pay phones at the Empire State Building delivering installments of a sci-fi radio drama? And what does all this have to do with the aliens who will attack Earth in 2552?

As these questions gripped tens of millions of Web surfers last summer and fall, the answers led to a viral marketing campaign created for Microsoft by Seattle-based 4TwoEntertainment to promote Halo 2, the long-awaited sequel to the Xbox videogame hit.

Ilovebees.com, the beekeeping site, served as the jumping-off point for an elaborate whodunit designed to generate buzz among gamers. The URL first appeared for a split second at the end of a Halo 2 promotional trailer. Gamers took the bait and swarmed the site. What they found was an innocent-looking homepage for Margaret's Honey bee farm that appeared to be hacked; an ominous block of cryptic text offered clues that set the sci-fi role-playing game in motion—until it mushroomed into a full-blown mania. During the four-month campaign leading to Halo 2's November debut, the beekeeping website logged 80 million hits, while thousands of players pieced together hints involving GPS coordinates and pay phones that all tied into the videogame's interplanetary-warfare storyline.

The massive buzz set the stage for Halo 2's hugely successful introduction. In its first 24 hours, the sci-fi shoot-'em-up pulled down an astonishing $125 million—the biggest debut in console videogame history. — THOMAS MUCHA