The Fringe teams from both worlds work together to aid a mutual cause.

Walter presents his theory to both Fringe divisions.

All of the cortexiphan kids work together and create earthquakes in both worlds.

David Robert Jones is trying to end both universes by using the cortexiphan subjects to do his dirty work.

The cortexiphan subjects believe the universes are at war.

Peter suggests severing the bridge between the worlds.

The Fringe teams try to find Jones so they can keep the bridge open.

Walternate decides they should close the bridge so at least one world can be saved.

Walter and Walternate connect deeply as fathers and scientists.

Goodbyes are said and the bridge is closed.