Theo Galavan might finally be dead in “Gotham” Season 2, but Jim Gordon and Bruce Wayne still have major problems. A villain from the past returns in episode 21, titled “A Legion of Horribles,” while a new face-changing character helps Professor Strange spread terror throughout the city.

Episode 21 of the Fox series begins with Selina (Camren Bicondova) attempting to escape Bridgit/Firefly (Michelle Veintimilla) and her flamethrower. Selina is able to use her climbing and fighting skills to get the upper hand on her brainwashed friend. She sneaks up behind Bridgit and knocks her out with a punch.

Bruce (David Mazouz) can’t find Selina, and he figures she is in trouble at Arkham with Hugo Strange (BD Wong). Meanwhile, Bullock (Donal Logue) is still acting captain of the Gotham City Police Department, and he briefs the press on Theo (James Frain) yet again being killed. Gordon (Ben McKenzie) wants him to take down Strange, but Bullock says he doesn’t have the evidence to do it. Bruce shows up at the GCPD and tells Gordon that something has happened to Selina.

The Court of Owls appear to be the ones pulling the strings behind Strange, and they’re not happy about what happened with Theo. Strange wakes up another subject, Basil, also known as Clayface (Brian McManamon), whose skin is now extremely stretchy. Ms. Peabody (Tonya Pinkins) warns Strange they could be shut down because their employer is interested only in immortality and bringing people back with their memories intact. He then decides it’s time to wake up Fish Mooney (Jada Pinkett Smith).

Lucius Fox (Chris Chalk), Alfred (Sean Pertwee), Gordon and Bruce come up with a plan to get into Arkham and find Strange’s secret lab where he’s turning people into monsters and keeping Selina. Bruce and Lucius will go on a “tour” while Lucius tracks the materials Strange is using on his patients. Lucius also agrees to get Gordon inside the Arkham gate.

Nygma (Cory Michael Smith) is back in his cell along with a fellow inmate known for eating people. Peabody mocks Nygma for running away while he tells her that he can help her and Strange stop Gordon and the GCPD. And he blackmails her by saying he knows what goes on in the basement.

Fish Mooney comes back to life and remembers exactly who she is. However, Strange chooses to keep her locked up, but she’s proof he can bring people back to life with their memories. Strange may have given her other abilities, too: When she touches a guard who brings her food, she’s able to command him to do whatever she wants.

Gotham Ep. 21 Fish Mooney (Jada Pinkett Smith) was brought back from the dead in “Gotham” Season 2, episode 21. Photo: Fox

While Strange discusses Fish, Peabody informs him that Bruce has arrived at Arkham, and Strange gladly welcomes Bruce and Lucius. Lucius goes on a tour with Peabody while Bruce asks to speak with Strange in his office. Lucius is also able to sneak Gordon in by hiding him in the trunk of their car, and Gordon enters Arkham disguised as a security guard.

While on the tour, Lucius uses a detector in an attempt to find traces of the materials Strange has hidden. In Strange’s office, Strange and Bruce begin to talk about the Waynes. Strange believes Bruce’s father got himself killed because he didn’t walk away from what was going on. Bruce takes this as a confession and ignores Strange’s warning that he should stop looking for answers. Instead, Strange has Bruce, Lucius and Gordon all taken into custody, just as Gordon finds the door to Indian Hill.

Selina tries use Bridgit’s flamethrower to burn her way out of the cell the two of them are in, but it’s fireproof. Bridgit then starts to wake up and she sees another flamethrower she can use on Selina. When Bridgit goes to attack Selina, Selina shoots fire at her, but it doesn’t do anything because she’s wearing a fireproof suit. Selina then seeks to get Bridgit to remember who she is, and when that fails, she convinces Bridgit that if she’s the “fire goddess,” she’ll need a servant, so Bridgit lets her live.

Strange is sitting in his office with Peabody when he gets a call from a woman with white hair. She says Strange has failed in his goal of finding a way to create immortality, but he then tells her about Fish and that he believes he can re-create what he did with her. Strange gets orders to move his patients to a new facility where he can continue his work. After he moves them, he has to destroy Indian Hill and any evidence of it.

Alfred goes to the GCPD after not hearing from Bruce and tells Bullock that everybody has gone after Strange in Arkham. Bullock uses his power as captain to assemble a task force to head into Arkham, rescue everyone and take down Strange.

Bruce and Lucius get taken to a cell where Nygma is overseeing them, as Strange decided to use Nygma’s help with Gordon and his team after all. Gordon gets taken by Strange, and Strange puts a strange box on Gordon’s head and preps him for an experiment. Nygma tells Lucius and Bruce to tell him everything they know and who they’ve told. Nygma gives them five minutes to tell him or they’ll get gassed to death.

Basil gets rolled into the room where Strange and Gordon are while Strange’s assistants take the box off Gordon’s head and place it onto Basil’s. When they remove it, Gordon is looking at a mirror image of himself. Strange plans to use this clone of Gordon to clean up the mess he believes they’ve all started.

“Gotham” airs on Fox Mondays at 8 p.m. EDT.