The arrival of a building from the alternate Earth causes massive death and destruction to those occupying the site at its arrival. Walter soon realizes that to equalize the balance between universes, another building will have to disappear... along with everyone inside it. The team's only chance is for Walter to activate Olivia's long-buried ability to distinguish objects from the other universe.

In an effort to remove Bell's consciousness from Olivia's mind, Peter, Bell, and Walter enter Olivia's subconscious and attempt to find her personality, which has hidden itself somewhere safe.