It's been nine months of anticipation, endless theorizing and analysis.
Tonight, a legion of devoted and often-obsessed fans will be begin their final descent into the nether world of "Lost," one of television's most complicated and engaging sci-fi dramas.
To be a "Lost" fan is often to be alternately mystified and slack-jawed. Each episode has been dissected at online fan sites run by devotees known as "Losties," some of whom rewatch portions of episides frame by frame to make sure they didn't miss one of the dozens of clues tossed out each week by the show's creators.
Because the show's creators rarely put anything into the show that doesn't have some sort of meaning, fans twist and turn with every plot line and look for hidden meaning in every nook. Books and comics read by the characters on the show are devoured for hints and characters' names are searched for possible anagrams.
There are two types of people in the world: those who follow every twist in "Lost" -- and those who have no idea what it's about.
In the nearly nine months since last year's season five finale, fans have had plenty of time to theorize what will happen to the characters they've come to know so intimately since "Lost" premiered in the fall of 2004.
When the screen went black in May, dark heroine Juliet had plunged down a cavernous hole and bashed a rock into the nuclear warhead that the time-traveling castaways had hoped would reset the past.
A 4-minute, 8-second video clip on ABC.com -- get Lost fans? Get it? -- recaps Juliet's struggle to set the bomb off, then gives spoiler seekers a peek into the world after. Or, some may say, the world before.
The rest of the events in the two-hour season premiere are anyone's guess. Show creators Cartlon Cuse and Damon Lindelof have been tight-lipped about the blast seen in the final minutes of last season, leaving fans to speculate whether it even happened and, if it did, who survived.
"Lost's" Jorge Garcia, who plays the wisecracking could-be-crazy Hugo "Hurley" Reyes, said he's been happy all along just to watch the show unfold with the rest of America.
"When we started to travel through time, we said, 'Oh, great, now where are we headed with this?' But I trust the writers. I was just like, 'OK, let's see how it's going to unravel,'" Garcia told ABC's "Nightline." "I'm the kind of person that likes to watch the magic trick happen, rather than trying to constantly figure out how they did it."
Michael Emerson, who plays the near-perfect villian Benjamin Linus, told ABC News NOW that he expects fans will be pleased with the season premiere.
Spoiler alert! Catch a sneak peek of the first few minutes of "Lost," which premieres this Tuesday, Feb. 2 on ABC at 8 p.m. ET.
"I think they have every right to expect to both enjoy and be perfectly satisfied by the final season," Emerson said, calling it "bigger, more climactic, more mind-bending than any previous season -- and that's saying a lot."
Return of the Dead: Boone and Charlie Ready for Their Second Act
Matthew Fox, who plays the island's tortured de facto leader, Dr. Jack Shephard, told "Nightline" that "Lost" worked right away because it was a show that demanded more of typically passive television viewers.
"I think there was a bunch of people out there who were really hungry for things that were going to surprise them and make them think and make them write their own version of the story, and I think those are the type of people who gravitated toward 'Lost,'" Fox said.
"I think it's a very demanding show. You have to pay very close attention, and it's not something you can sort of just pop in and out of," he said. "It's not something you can just passively sit back and watch. You have to actively participate in it. You have to look for clues in it. And there is a certain segment of the TV audience that really enjoys that."
Fans are also expecting the return of characters previously killed off -- including Charlie, played by Dominic Monaghan, now of "FlashForward" fame, and Boone, played in the first season by Ian Somerhalder. Also returning is Emile de Ravin in the role of young mother Claire, who wandered into the woods in season four and left her baby to be raised by Kate, the freckled fugitive.
While the show has leaned heavily on sci-fi elements like time travel, portals and a shape-shifting black smoke monster, it largely remains a character study.
So when "Lost" lights up the small screen for its final season, fans will eagerly anticipate the resolution to the Jack-Kate-Sawyer love triangle. Sawyer had gotten all cozy with Juliet in season five, but since her face was about five inches from the nuclear blast in the season finale, Sawyer could very well be back in the running for Kate's affection.
"It feels like a show about all of us," Fox said, "and if you're willing to go on that ride and if willing suspension of disbelief is something you're into and you like to play with that, it's a good ride."
Losties will also want to know whether Sun and Jin -- currently both on the island, but stuck 30 years apart -- will ever meet again and whether Jin will meet the miracle daughter he conceived on the island.
Will Jack forgive himself that his father -- who, by the way, may or may not be dead -- fell off the wagon? Will Ben pay the ultimate price for his scheming ways? And will any more polar bears slip through the portal?
Man of Science vs. Man of Faith: The Final Showdown
Some critics complained midway through the show's run that its creators and producers were losing focus, drawing viewers deeper into a web of questions that may have no answers.
But last season's concluding episodes seemed only to solidify the mind-bending plot lines of good versus evil, destiny and spirtuality that have stretched across all five seasons.
At the center of the show's debate of faith is John Locke, played by Terry O'Quinn. His storyline was intense from the very first season, when it was revealed the man, who was up and walking around the mysterious island, had boarded Oceanic flight 815 in a wheelchair, paralyzed from the waist down.
Even O'Quinn's character's name has been the subject of intense analysis -- John Locke was also a 17th century philosopher who influenced many of the Enlightenment's greatest thinkers.
O'Quinn told "Nightline" that the show's final season has been a mixed blessing for him.
And even though he is as famously tight-lipped as the rest of the cast and crew, O'Quinn said his expectations are just as high as the viewers'.
"They have so many balls in the air. I hope they can catch most of them," he said of the show's writers. "It's going to be more than who gets the girls, it better be more than who gets the girl and I'm sure it will be. But they have the burden of producing of delivering on those expectations."
Through much of the show, O'Quinn's Locke has butted heads with Fox's Shephard.
As the island's only doctor, Shephard has been burdened by a heavy sense of duty to his fellow castaways, and haunted by a previous life in which he watched his father nearly destroy his career with alcohol. He nearly did the same thing to himself after being rescued at the beginning of season five.
But now, after five full seasons, Fox said he finally has his doctor figured out.
"I think that Jack has finally reached his point in the middle of the fifth season where he really knows who he is and what he's meant to do," Fox said. "Getting there was a huge relief. Because the struggle of this guy and his own self-doubt and being his own worst enemy, and this whole argument of science versus faith and destiny -- he's had a long transition to go through to finally reach the point that he's really committed to the notion that his whole life has been bringing him up to this point."
The cast and crew are still in the dark about the finale. Emerson said they are only about two-thirds of the way through filming the show's final season.
For Emerson and many of the show's other cast members, the end of the show will mean leaving the island paradise they've called home for more than five years.
"It'll be sad," Fox said. "I'm going to savor this next couple months, saying goodbye to this story."
"At the same time," he said, "there is a huge part of me that's excited about the next chapter of my life."