An airplane goes down over the south pacific. The survivors are on an island and very early on, they encounter strange happenings on this island. There are central characters and their backstories are interspersed into the what’s going on on the island. We gradually learn that some of these people are loosely connected to one another. Most importantly, we discover there are hostile inhabitants already on the island.
As a result of one of the main character’s weird “connection” to the island, he/we discover a hatch that leads to an (almost) abandoned scientific research station, the first of many we will encounter. This scientific research group arrived on the island decades ago and their true motives haven’t completely come to light, and was apparently kept secret even from some of it’s members, but it appears that their ulterior mission had something to do with “saving the world” and the space and time travel abilities of the island. This research group was eventually decimated years ago by the aforementioned group of hostile inhabitants.
The history of these hostiles is shrouded in mystery, as is the nature of the island. These include:
A mysterious “security system” in the form of a scary black smoke moster that makes mechanical sounds. This entitiy is able to take the form of people from it’s “victim’s” past. It can be summoned by unknown means but cannot cross a giant sonic fence erected on a portion of the island.
People have either hallucinated or actually encountered deceased people from their past.
The island has been suggested to either being sentient or at least permeated with sentient forces that can alleviate longstanding injuries or diseases and disabilities even of people who have left the island, but, curiously fetuses concieved on the island die midway through pregnancy.
There is an old slave ship that somehow came aground far, far, far inland on the island.
There is evidence of a previous civilization on this now-deserted-appearing island, evidenced by a giant 4-toed statue and a weird cold subterranean wheelhouse that can apparently move the island. Possibly through time as well as space.
The “hostiles” or “Others” are refer to themselves as the “good guys” and are —or were, until recently — led by Benjamin Linus, a master-manipulator. These others have lots of resources at their disposal and were able to leave the island at will. They use the homes built by the scientific research group and are able to learn/know a great deal about the castaways. It is being suggested that they are in a struggle against a rich and powerful man named Widmore to keep him finding the island.
Several of our main characters have recently made it back to civilization, but there has been some strange phenomena in their lives that are alternately driving them crazy or suicidal. They are apparently driven to return to the island.
J.J. Abrahms has mentioned that one of his goals with the show is to keep things shrouded in mystery until the very end. He was inspired by this “Box of Magic” he got as a child and has never opened, citing that the possibilities of what might be in the box is itself a thrilling experience.
Thus, anyone looking for instant gratification as to what the hell is going on is going to be aggravated with this show. People who think getting there is half the fun and enjoy the ride and like to hypothesize based on the clues that are gradually doled out love this show.