After young Ben got shot by Sayid in the jungle, he's still alive and Jin brings him back to be treated. Juliet cannot fix him completely and Jack refuses to do a surgery on him too. Kate, while in flashbacks remembers how she ended up with Aaron, takes young Ben with help of Sawyer to Alpert to save his life, but he warns them if he takes him, his innocence will be gone, something Kate and Sawyer accept. At the end, Ben (real one) wakes up while Locke is sitting next to his bed and surprise him by saying him "Welcome back to the land of the living". In this Kate-centered episode reveals that Kate gives Aaron to his grandmom before getting back to the island and how actually Ben becomes one of OTHERS. My vote is eight.
Review of Whatever Happened, Happened
