Evelyn decides to radio Marcus to negotiate a peace treaty.
In the hallway, Peter is ready to get erased. So Tobias gives him the vial of memory serum. Peter drinks it. ("Mmm… tastes like… I don't remember what things taste like.")
Tobias leads the erased Peter to Millennium Park, where Evelyn meets with Marcus and Johanna.
Johanna, as the leader of the Allegiant, agrees to Evelyn's terms: Evelyn will surrender her weapons, and people will be allowed to leave the city if they want to… as long as Marcus minds his own business and doesn't try to lead anything anymore. Not even a conga line, Marcus.
Tobias says good-bye to Marcus for the last time and goes to tell Uriah's family what happened to their son.
The group rides back with him to the compound, where they realize Tris's plan worked.
Well, except for the whole Tris dying part. Um, sorry, Tobias. That stinks.