This contains the entire episode of "Across The Sea", where we see Jacob's origins, along with his brother. We also see the earliest time flash, when Locke turns the wheel to stop the island from moving.

In episode 002, we pick up with Richard Alpert in 'Ab Aeterno'. In between his time in prison and crashing on the island, we see Jacob's conversation with the Man in Black before the Black Rock arrives. The episode concludes with another time flash, when everyone flashed to 1954, with Locke reuniting with Sawyer, Juliet & Co

We play out the rest of the time flash in 1954, then we go on to see Locke born in 1956, then visited as a child by Richard. We also see Ben born, as his mother dies, and eventually ends up on an island. The ending to this episode is a little anti-climactic, with Ben meeting Richard in the jungle, but it was done to create a bit of a bookend for the next episode.