We start Episode 004 with the final time flash that lands everyone in 1974, where they encounter the Dharma Initiative. In between 1974 and our first glimpses of 1977, we see Sawyer around the time of his parents' death. The episode concludes with Jack, Kate, and Hurley waking up on the island after taking Ajira 316 to get back to the island.
This episode runs 45:51 and is approximately 390MB to download. You can stream below (via Facebook), or go here to use torrents (better quality, recommended) to download the episodes to your computer.