It's Day 2 on the island and Sarah is certain she's seen Alan Farragut in the distance. That's confirmed as she watches the cultists in their religious service and a very ill boy, Soren, barges into the room. Sarah and Alan make eye contact. The CDC team want to find another older boy, Isaac, who had similar symptoms but has run off. When she finally gets a chance to speak to Alan - they've not seen each other since the events at the Antarctic station 15 months ago - Sarah has a revelation of her own. In the future, Julia digs up Alan's grave looking for a clue and finds several different sets of bones.
—garykmcd