Lucius Fox (Chris Chalk) will create Batman’s first suit in “Gotham” Season 4. FOX

Bruce Wayne (David Mazouz) is slowly transitioning into the Batman in the fourth season of the Fox show “Gotham.” He donned a prototype suit during the Season 3 finale as he rescued an unsuspecting family from a criminal, but in the trailer for the upcoming season, Bruce is seen wearing a better-looking suit and mask.

Executive producer Danny Cannon told TV Line that this new suit and mask is all courtesy of Wayne Enterprises executive-slash-police forensic scientist Lucius Fox (Chris Chalk).

“Yes, Lucius is beginning to suspect that Alfred (Sean Pertwee) and Bruce might have a double life and politely weaves his way in,” said Cannon. “Lucius has worked for Wayne Industries and he may work there again one day, and for right now he doesn’t want to see Bruce get hurt. So he finds a way of helping without interfering.”

However, not everybody from Bruce’s life would be keen to help him. Some of them won’t even know what he’s up to, including his friend, Detective Jim Gordon (Ben McKenzie). Bruce is helping clean up the streets of Gotham City by getting rid of its villains, therefore gaining notoriety as a vigilante crimefighter. This does not sit well with Gordon, who makes it his mission to discover who this new crimefighter is.

“Jim Gordon will realize that this vigilante is operating out there in Gotham somewhere and he goes ‘I’m going to hunt that guy down’ and we have Jim Gordon and a masked Bruce Wayne going head to head,” co-executive producer John Stephens told Comic Book.

Still, Gordon’s main priority would be to take down the Penguin (Oswald Cobblepot), who managed to take control of the Gotham City underworld and even open up his own bar, the Iceberg Lounge. “In the first half of the season this year, Jim Gordon is going to try to loosen Penguin’s hold upon Gotham,” Stephens told DC All Access. “He does that by forming an alliance with Sofia Falcone, who Crystal Reed is playing, and the two of them work together to basically try to dethrone Penguin.”

“Gotham” Season 4 will premiere on Sept. 21 on Fox.