After discovering David's plot to wipe the memories of everyone in Chicago, Four tries but fails to convince Tris to return with him to Chicago. Tris leaves with David to Providence while Four is taken back to Chicago by Romit and other Bureau soldiers. However, Matthew warns Four that they are not taking him back to Chicago which results in a fight in the aircraft and causes the aircraft to crash with only Four and Matthew as survivors. Four returns to Chicago alone and is captured and placed in a cell in Erudite. Tris and David meet with the Council and Tris discovers David's true intentions. After returning to the Bureau, Matthew, on Four's request, lies to David and tells him that Four left him behind after the crash. Tris knows this to be a lie and enlists Caleb's help in locating Four. Meanwhile David sends Peter back to Chicago with the memory serum. Tris steals David's aircraft and escapes along with Caleb and Christina. Upon arriving at Erudite Headquarters Tris and Christina rescue Four while Caleb searches for a way to halt the release of the memory serum in the city. Four convinces Evelyn not to release the serum but Peter shoots her. She survives but the memory serum is released upon the city including Erudite headquarters. Tris and Four convince Peter to open the door to the vault and Tris stops the serum from being released by destroying the valve. Tris, Four, Caleb, Evelyn, Johanna, Christina, and Uriah go to the roof the Erudite Headquarters where Tris sends a message to David that he will be defeated. David, however, using his own surveillance technology is watching.