Calling Lost’s sixth and final season its most unpredictable would be an understatement. The prior season concluded in uncertainty with a white flash filling the screen following the detonation of a hydrogen bomb. Almost immediately after that flash, the speculation for the show’s final season began to mount. Did the bomb successfully reset the events of the series as the characters had hoped that it would, or did the bomb destroy all the characters in its wake? As the questions and theories amassed, never had a period of time between Lost seasons felt so long.

Those questions are immediately addressed in “LA X,” the season’s first, two-part episode, but it just isn’t Lost without a bit of toying with the audience. This episode introduces an entirely new concept — the flash-sideways — an alternate universe in which the Flight 815 crash never occurs and the characters land safe and sound in Los Angeles. Though as the season progresses, the flash-sideways becomes more than an “if the 815 Flight had never crashed” scenario as the episodes focus on certain characters whose lives had obviously been altered long before the flight even took off from Sydney. In “The Lighthouse,” for instance, it is revealed that Jack has a teenage son, and in “Recon,” Sawyer is shown to be a cop instead of a con man. We begin to see shades of the survivors bettering themselves in the alternate universe and attempting to correct their mistakes made in their other lives on the island. The episode “Dr. Linus” presents a completely different Ben Linus — a compassionate schoolteacher that mentors Alex, his on-island adopted daughter who was killed in season four after Ben chose the island over her life.

Within this season is also the concurrent on-island timeline, of course, in which the hydrogen bomb goes off and transfers those survivors stuck in the 1970s back to the present. This leads to much discovery on the island and, in turn, some answered questions. “The Substitute” is the most telling episode of the season, uncovering the mystery behind the fated Lost numbers (4 8 15 16 23 42, as if you needed a reminder). In that episode, the Man in Black (stuck in the guise of John Locke) takes Sawyer to a secret cavern on the far end of the island, where Jacob had been assigning numbers to each of the names of individuals he felt would be suited for the position of the island’s protector upon his death. This sets the stage for the island’s most telling feud between the MIB and Jacob’s Candidates (Sayid, Sawyer, Jack, Sun, Jin, and Hurley); both sides want to escape the island, but neither can afford for the other to succeed.

Despite what seems like a clear-cut good-versus-evil battle between the Candidates and the MIB, several episodes of the season tinker with viewers’ feelings toward the island’s two oldest inhabitants, Jacob and the MIB. The MIB appears compassionate in episodes like “Sundown,” in which he offers Sayid the opportunity to again see the woman that he loved (Nadia) in exchange for delivering a message to the Temple Others. The MIB also offers answers to Sawyer (in the aforementioned “The Substitute”) as well as Jack (in “The Last Recruit”) when he reveals that he was behind the apparition of Christian Sheppard (Jack’s father) that led Jack and the other survivors to water in the first season. If there is a character most forthcoming this season, it’s the MIB. On the other side of that coin is Jacob, who throughout the season is frustratingly vague. It was never explained who Jacob wanted Hurley and Jack to bring to the island in “The Lighthouse,” and his initiation of Jack in “What They Died For” as Jack takes over for the fleeting Jacob is not only confusing but undeniably silly. Jack drinks water from the island, and Jacob proclaims, “Now you’re like me.” What does that mean?

In the latter half of the season, “Across the Sea” proves to be the season’s most frustrating episode. Here we’re given the long-awaited back story of the MIB and Jacob in an episode that only adds to the mystical malarkey of the island. Neither Jacob’s sudden desire to protect the light at the heart of the island nor the MIB’s creation of the wheel that moves the island is ever explained to the point that it doesn’t seem ridiculous, even to the diehard Lost fans who accepted the whole “think of the island like a record spinning on a turntable” explanation for the time travel in Season 5. In stark contrast to this episode is “Ab Aeterno,” one of the season’s best. This episode shines a light on the island’s most mysterious inhabitant, Richard Alpert, and chronicles his journey to the island. Along the way we understand his motivation and sympathize with his plight of losing his wife and then being chained aboard the Black Rock. It is in this episode that we also see more temptation from both the MIB and Jacob as the two proclaim that the other is “the Devil.”

It becomes clear in “The Candidate” that the MIB is truly the “evil incarnate” he was deemed to be as his actions result in the sudden death of Sayid, Sun, and Jin. These deaths, coming so late in both the season and the series, help not only to solidify the MIB as the primary threat to the island but also to establish Jack’s motivations for wanting to take over for Jacob in “What They Died For” and stop the MIB. Of course with the series still reaching into the alternate universe each week, Sun, Jin, and Sayid are never truly gone, yet the shock of their sudden death still stands out as one of the season’s more memorable moments. Other deaths on the island, including those of Illana, Dogan, and Lennon, are underwhelming. Illana, the proclaimed protector of the Candidates, has her most important moments off the island (helping Desmond in the alternate timeline gather the 815 Flight survivors together) after her death in “Everybody Loves Hugo.” Dogan and Lennon, two of the Temple Others, are throwaway characters in a throwaway subplot involving a mysterious Temple on the island that was, presumably, a hideaway for Jacob even though the MIB has no problems running through that place in “Sundown” and killing everyone inside. Some sanctuary.

“The End,” the season and series finale, will polarize fans for as long as Lost is remembered. The final moments of the episode, in which Jack lies down in his final resting place on the island while simultaneously meeting his father and accepting both of their deaths in the alternate timeline, is truly the culmination of Jack’s change from a man of science to a man of faith. Ever since the opening moments of the pilot, Lost has been about Jack testing his faith. Gradually he came to believe that the island, no matter how ridiculous the events on it may seem, is worth protecting. If you are someone who could believe in the island just as Jack did, then chances are the finale was masterful in your eyes.

Still, it feels as though the show does not wrap up its entire run with “The End,” just its first and last seasons. It is disheartening to know that those looking to tie loose ends like what the importance of Walt was in the first and second seasons or how the numbers were featured so prominently on the island before the Candidates arrived will not be able to do so with any certainty; fan theories posted on the internet will have to suffice. The idea that the polar bears were trained to turn the wheel that moves the island, for instance, sounds plausible, but it’s just an unproven theory found online amongst hundreds of others. In a way, though, the finale perfectly encapsulates Jack’s own personal discovery. Some will find that their faith in the island negates all the unanswered questions while others will prefer a more concrete closure to their budding queries. Nevertheless, the entirety of Lost’s final season, much like the five seasons before it, is ripe for dissection and interpretation among its viewers, whether those viewers are of science or of faith.