LOST

Their are six seasons of Lost.

Season 1:

This season features 25 episodes. A plane crash strands the surviving passengers of Oceanic Flight 815 on a seemingly deserted tropical Island, forcing the group of strangers to work together to stay alive. Their survival is threatened by mysterious entities including polar bears, an unseen creature that roams the jungle, and the island's malevolent inhabitants known as the "Others". They encounter a French woman named Danielle Rousseau who was shipwrecked on the island over 16 years earlier and find a mysterious metal hatch buried in the ground. An attempt is made to leave the island on a raft.

Season 2:

This season features 24 episodes. Most of the story, which continues 45 days after the crash, focuses on the growing conflict between the survivors and the "Others", with the continued theme of the clash between faith and science being important in certain episodes. While some mysteries are resolved, new questions are raised. New characters are introduced, including the tail-section survivors and other Island inhabitants. More island mythologies and insights into the survivors' pasts are divulged. The hatch is explored and the existence of the Dharma Initiative and its benefactor, the Hanso Foundation, are revealed. As the truth about the mysterious "Others" begins to unfold, one of the crash survivors betrays the other castaways, and the cause of the plane crash is revealed.

Season 3:

This season features 23 episodes. The story continues 67 days after the crash. New crash survivors and the "Others" are introduced, as the crash survivors learn about the "Others" and their history on the mysterious Island. One of the "Others" and a new Island inhabitant join the survivors while a survivor defects to the "Others". A war between the "Others" and the survivors comes to a head, and the survivors make contact with a rescue team.

Season 4:

This season features 16 episodes. The season focuses on the survivors dealing with the arrival of people from the freighter Kahana, which has come to the Island, and the escape of the Oceanic Six (their post-island deeds being shown in flash forwards).

Season 5:

This season features 17 episodes. Season five follows two timelines. The first takes place on the island where the remaining survivors erratically jump forward and backward through time until they are finally stranded with the Dharma Initiative in 1974. The second continues the original timeline which takes place both off the island and following the Oceanic Six's return to the island on Ajira Airways Flight 316 in 2007.

Season 6:

This season features 18 episodes. Season 6 shows other versions of the characters stories in a non-Island setting, referred to as "flash sideways". In the real world, the survivors return to the present day and must deal with the demise of Jacob, whose death has been orchestrated by the mysterious Man in Black, the Smoke Monster. According to show producer Damon Lindelof , the term "flash-sideways" was deliberately used instead of "alternate reality" because it might then imply "that one of them isn't real, or one of them is real and the other is the alternate to being real." The final episode revealed that the flash-sideways timeline was actually a form of the afterlife, which the survivors themselves created as a gathering place once they had all died. The flash-sideways reality did not imply anything about the circumstances where they died. As Christian Shepard said, some died long after some others, meaning some lived on after leaving the island.