Complete story — includes the ending
Jerome holds the interim mayor and other powerful Gothamites hostage at a music festival and orders Gordon to bring him, Bruce, and Jeremiah, buying time for the other Legion members to load the laughing gas onto a blimp and release it upon the festival crowd. The GCPD takes out Jerome's men and saves the mayor, while Cobblepot betrays the Legion by subduing the pilot and steering the blimp away from civilians. Gordon pursues Jerome, who declares that he will live on and willingly falls to his death from a rooftop. Barbara learns more of her alleged destiny as the League of Shadows' leader, but Tabitha believes she is delusional; Barbara severs ties with Tabitha, who is then taken by another League faction still loyal to Ra's al Ghul. Tricked into opening a "gift" left by Jerome, Jeremiah is exposed to a modified version of the laughing gas that drives him insane.
Sources and content license
Source and revision history · Adapted from Wikipedia contributors, Gotham season 4. HTML formatting and reference markers removed. · Content license