LOST IN NUMBERS: Four Things To Remember From The Season Five Finale

DESCTime travel. Hydrogen bombs. Sudden deaths. Shape-shifting imposters. These were just a few of the shocking developments that took place over the course of the fifth season of "Lost," which aired its finale in May of 2009.

With any luck, the final season of "Lost," set for a two-hour debut on February 2, 2010 starting at 9:00 PM EST, will address these points and much more. But going into the season premiere ("LA X"), there are a few essential elements from the most recently aired episode that can't be forgotten.

After the jump, we've got the rundown on four important facets of season five's finale to remember as the final season's premiere awaits. Stay tuned to MTV for the rest of this week and into the season premiere, as we'll be running a series of features pegged directly to the show's trademark number sequence: 4, 8, 15, 16, 23, 42. Needless to say, spoilers for season five and earlier lie ahead.

1. Exit '77: A significant portion of "Lost's" fifth season focused on our central heroes — Jack, Kate, Hurley, Sayid, Sawyer, Juliet, Jin, Miles and Daniel — who were trapped in 1977 as members of the DHARMA Initiative. Some of them, like Sawyer and Juliet, were perfectly content with their new lives, while others, like Jack and Sayid, struggled to find their purpose in the old era.

Ultimately, Daniel devised a plan to detonate a hydrogen bomb in the yet-to-be-built Swan Station, thereby preventing the Lostaways from ever coming to the Island in the first place. Following Daniel's death, Jack followed through on the plan, leading to a cliffhanger moment where the device seemingly went off.

2. Bombs Away: The ramifications of the bomb's potential detonation are enormous. If the bomb went off, what happened to the castaways? Did Jack et al die in the blast, as Richard Alpert once professed to have seen? Did Faraday's plan work, effectively ending our heroes' stay in 1977 and changing the course of history?

Assuming that the mission was successful, there's no telling what the landscape of "Lost" will look like going forward. Alternate realities are the popular theory, though some are worried that the continuity of the first five seasons will be rendered worthless by this one explosive action. If nothing else, expect a drastic change in the show's narrative style as teased by showrunners Damon Lindelof and Carlton Cuse.

3. Dead is Dead: Death is no stranger to the "Lost" community, with fan-favorite characters like Charlie Pace, Mr. Eko, Michael Dawson and more succumbing to the reaper over the course of the show's five years. The fifth season was particularly brutal towards the main cast, claiming lives such as Charlotte Lewis, Daniel Faraday and — most likely — Juliet Burke.

But the greatest death of them all was John Locke, murdered at the hands of the duplicitous Benjamin Linus. Viewers have known about John's impending death since the fourth season finale, but his seemingly miraculous resurrection upon return to the Island was a shocking development not just for the audience, but also for the surrounding characters. Of course, few things on "Lost" are what they appear to be...

4. Unlocked: Aside from the bomb's potential detonation, the most stunning moment of the fifth season finale was the revelation that John Locke is still dead, meaning that some sort of imposter had been using his likeness for the majority of the season. This man — commonly referred to as the Man in Black, or MIB for short — is responsible for the death of Jacob, one of the Island's mystical inhabitants, murdered by Ben at "Locke's" own request.

It's still too early to say exactly who or what the MIB is. Many have speculated that he's the Smoke Monster — a theory I've embraced myself — or that he's in league with the creature. Whoever or whatever he is, the MIB is undoubtedly of huge importance in the final season of "Lost," as indicated by Terry O'Quinn's prominent placement in the show's promotional material.

Check back tomorrow for another edition of LOST IN NUMBERS, a series of daily features running until the final season premiere of "Lost" on February 2, 2010.