Mad Hatter sets his eyes on his next victims, forcing Jim Gordon to make some tough decisions. Meanwhile, Penguin and Nygma's relationship evolves, and a familiar face comes back into Nygma's life.

After coming in contact with a substance by the hand of Mad Hatter, Jim Gordon gets led on a psychedelic trip and must confront his past, present and future. Meanwhile, Penguin struggles with Nygma’s new relationship.

The effects of a recent incident begin to cause Barnes to go mad; Nygma is over his head in his relationship with Isabella; Carmine Falcone throws an engagement party for Lee and Mario.

Gordon and Bullock sift through evidence from the murder at Lee and Mario's engagement party; Ivy discloses her identity to Selina and Bruce.