Please fasten your believability seatbelt. The following summary may produce mental turbulence .

"Lost" began when Oceanic Flight 815 from Sydney to Los Angeles crashed on a South Pacific Island. The survivors were all strangers, but would discover hidden connections in their lives as they encountered a malevolent smoke monster, a colony on the island of sinister residents and a secret project to tap into the island's hidden energy and allow for time travel.

By Season 5, some of the survivors were rescued, while others found themselves skipping through time. Some of them wound up in 1977, while the rest remained in 2007. Eventually, all of them wound up back on the island.

One of the survivors living in 1977 believed he could change the course of events by detonating a hydrogen bomb he found on the island, negating the energy that had originally sucked Flight 815 out of the sky, so that when the plane ultimately arrived over the island, it would not crash.

When the bomb was dropped into a deep hole in the island, however, it didn't explode. Fortunately, one of the survivors fell into the hole, and with her dying breath, detonated the bomb by smashing a rock against it.

And so began the beginning of the end. Welcome to Season 6.