Hard to say, really, which moment packed the most punch. There was the kidnapping of a child by spooky sea hillbillies, or the unexpected detonation of a new character by dynamite. The landlocked slave ship. The anthropomorphic smoke demon. The crazy French chick stealing the baby. The heroin addict’s apparent relapse. Or maybe it was the bio-mechanical island monster uprooting trees and dragging people underground. Tough call.

I’m talking, of course, about the season finale of ABC’s paranormal castaway drama Lost. TV’s most ambitious new show wrapped up its inaugural season with a stellar two-hour episode that hit on all cylinders. It sustained the season’s delicate calibration of character study and action, as the 40-odd survivors of Oceanic Flight 815 have been dealing all season with seeming miracles and certain terrors. The headcount has varied, as the show is famously unafraid to kill off heroes in service of story. (Good creative policy, but you have to figure it makes the actors nervous.)

The finale had the castaways facing off against “The Others,” an as-yet unseen island faction that may be responsible for all the weirdness. Lost trades heavily on misdirection and plot twists, so the face-off wasn’t what — or even where — you expected. The much-hyped cliffhanger ending came in the terrifying penultimate scene, with the final moments offering more of a thematic resolution. In the last shot, the camera lingered on our three ostensible leads — rational hero Jack (Matthew Fox), creepy mystic Locke (Terry O’Quinn), and mercenary babe Kate (Evangeline Lily) — as they peer down the tunnel beneath the mysterious hatch. Who will lead? Tune in next fall.

Over the course of its first season, Lost proved much more than the sum of its parts. Plane crash? Desert island? Nascent society? Yes, we’ve heard this story before, in forms as diverse as Lord of the Flies and Gilligan’s Island, but Lost switches up the rhythms. Its deft admixture of (seemingly) supernatural elements shifts the tonal palette into Twilight Zone territory, while the ongoing mythology mystery puts it in the bloodline of The X-Files and Twin Peaks, two shows to which it is often compared. A story this multifaceted needs a sturdy armature for narrative traction, and in that sense the mythic stranded-in-the-wild story has proven effective for a few thousand years now.

As with The X-Files and Twin Peaks, though, it’s the central mystery thread that hooks: What the hell is going on?. Half the fun is trying to outguess the writers, and literally hundreds of theories are documented on various online fan sites. (The message boards at www.lost-tv.com are best.) I have a theory myself, an insanely complex and frankly brilliant hypothesis involving AI, temporal shifts, and nanobots. I am confident I shall be proved prescient in Season Two.

Beyond the plot twists, though, Lost features recognizable characters and emotional stakes. For a show so very pop (nearly pulp) in concept, it has shown an admirable willingness to tackle both big issues (faith vs. science; free will vs. fate) and delicate character arcs. Its liberal use of flashback sequences illuminates the latter while expanding plots past the boundaries of the island. The flashbacks indicate the multivalent nature of the show and its title: this is a story about human beings who were, in some way, lost well before they boarded their flight.

For example, Matthew Fox’s character, Dr. Jack Shepard, has emerged as a moral axis. In the first few episodes, he seemed a standard-issue square-jawed hero — a natural leader, conscientious and reliable, if a little humorless. Subsequent flashbacks revealed deeper (and darker) layers, each new revelation about his past then reflected in the present storyline. And the finale presented a still more complicated portrait — a conflicted man of medicine trying to control events that will not be controlled.

Against the flashier dramas of Locke or the addict Charlie (Dominic Monaghan), Fox’s contribution is easy to miss, but Jack’s story is the core of Lost. To ease the burden of his perpetual seriousness, the series turns to peripheral characters for leavening. The Zen slacker Hurley (Jorge Garcia) shoulders most of the comic relief, but little gags occur regularly within developing conflicts. Hurley’s flashback sequences — expanded on in the finale — provide some of Lost’s funniest and most touching moments.

These quieter flourishes hint at Lost‘s true heart: The show presents as a sci-fi freakout (it’s certainly marketed as such), but the creators have a much more fascinating and complex topic in mind — people.

And there resides the unstated question, posed as a weirdly intimate kind of subtext. In this situation, you could start over completely — reinvent yourself and your life. Some theories suggest the island is a kind of purgatory, a spiritual waystation, a place to begin again. None of the old rules apply, and there may be magic involved. Would you lead? Would you follow? Would you surrender to the island, like Locke, or attempt to manage it, like Jack?

Or maybe you’d just do the practical thing — run like hell when the monster shows up. Lost can be enjoyed on any or all of these levels. Part sci-fi thriller, part melodrama, part existential mystery, Lost is a cross-genre mash-up with the creative heart of an adrenalin junkie. The thrills are not cheap — they’re earned — and that’s what finally makes the show worthwhile for the loyal viewers who consumed this first season in thirsty gulps.