It reboots the series with the pilot again, only this time the people who were touched by Jacob remember the last time they did all this.
The plane still crashes, and once Jack has been sewn up, and they stop the first red shirt from being sucked into the engine, Jack, Kate, Sawyer, Jin, Sun, Hurley and Syied all go to the back door of the hatch, Desmond opens the door, and knows who each of them are.
Meanwhile Faraday is watching tv, and when the news report of the flight going missing comes on, he has a moment of clarity, and starts remembering everything too.
As the season goes on they start altering events with their prior knowledge of what has happened before.
They tell Ethan they know who he is, and who sent him, and request a meeting with Ben and Richard, at the same time they send people to the other side of the island to help the tailies.
Back in LA, Daniel meets with his mother and Widmore in an attempt to break the cycle from their end too.
Jack and Sawyer convince Ben and Richard to have a truce based on their insider knowledge of events like Jughead and Jacob.
There is no war between the survivors and the others, but then a mysterious 3rd party turns up on the island