Carlton Cuse and Damon Lindelof, the executive producers and showrunners of "Lost," have sworn that they never introduce an element into the plot of their astonishingly complicated serial drama unless they already know how it'll resolve itself.

They also swear that they ended up exactly where they wanted to be at the end of Season Two, which means they're either incredibly lucky, or incredibly meticulous. It's probably some combination of both, really.

Since its debut on ABC in the fall of 2004, "Lost" has evolved from an enticing curiosity into an all-consuming mystery epic, with a mythology that seems as limitless as it is coherent. And the second season is where it all comes together, with the arrival of new characters, the discovery of the Dharma Initiative, and creepy new revelations about the nature of the merciless Others.

Along the way, the show hit a couple of speed bumps -- not the least of which was the year-long irritation of Michelle Rodriguez as an obnoxious hothead ex-cop who never seemed quite as sympathetic as the show insisted she had to be -- but Cuse and Lindelof recovered nicely, turning the final run of episodes into a breakneck psychological thriller, ending on a cliffhanger that promises a third season as tonally distinct from Season Two as, well ... as "Lost" is from anything else on television. That's going to be something to see.

Buena Vista's boxed set distills the entire season -- in enhanced widescreen and Dolby Digital, true to the intended HDTV presentation -- onto six discs, with extras limited to cast-and-crew commentary for "Man of Science, Man of Faith" on Disc One, "What Kate Did" and "The 23rd Psalm" on Disc Three, "The Whole Truth" on Disc Four and "Dave" on Disc Five.

But it's Disc Seven that will surely keep the faithful busy until the series returns in October -- a supplemental collection, billed as "Lost: The Extended Experience," packed full of additional mysteries.

Presented as one of those deliciously opaque Dharma Initiative orientation films, the disc offers three separate sections.

"Phase I: Observation" is the conventional making-of material, with a half-hour look at the production of the episode "Fire + Water," ten "Lost: On Location" featurettes totalling an additional 45 minutes of behind-the-scenes footage, and "The World According to Sawyer," a silly little featurette that lets the cast share their favorite memories of everyone's favorite redneck.

"Phase II: Conditioning" pops the top on 14 deleted scenes, three deleted flashbacks, a blooper reel and a lovely video shot by David LaChapelle for British television. (If you've only seen it online, the quality of this version will take your breath away.)

Finally, there's "Phase III: Conclusion." If the previous phases sounded like ordinary DVD supplements, this one makes good on the promise of going further and deeper into the show than ever before.

There's "Secrets from the Hatch," a 15-minute look at the conception, construction and employment of the elaborate Dharma Swan station, celebrating both the mesmerizing detail of the gargantuan set and its remarkable impact on the characters.

The 10-minute featurette "Mysteries, Theories and Conspiracies" explores certain symbols and icons that recur throughout the season, including those accursed Virgin Mary statues and the mysterious Alvar Hanso.

And finally, there's "Lost Connections," which uses an insanely complicated interface to illustrate the seemingly endless connections that exist between the passengers of Oceanic 815. Pick a character, and follow the strands that connect him or her to just about everyone else on the flight ... but be ready to spend a few hours in front of the TV doing so. It's kind of irresistible.

STUDIO: Buena Vista Home Entertainment
RELEASE DATE: September 5, 2006
RATING: Unrated
PRICE: $59.99
TIME: 1065 minutes
DVD EXTRAS: English subtitles; audio commentaries; deleted scenes; production featurettes; interactive character guide.
INTERNET SITE: www.lostondvd.com/