Gotham as TV show had many a fans psyched about The Dark Knight's outing on television, but many hopes were dashed, as the series revolved around The Batman Universe before Bruce Wayne put on the cowl & cape, but things will take a turn in Season 4 :D
The season will journey through the beginning of The Batman and how Bruce Wayne finally embraces his alter-ego in the quest to become Gotham's saviour. Excerpt from David Mazouz's (The actor who plays the young Bruce Wayne on the show) interview to Comicbook.com:-
"Bruce really is taking on this vigilante persona and all the things that go along with that," Mazouz revealed. "Whether it be creating another persona, a public persona, that’s also definitely going to be a major part of Bruce’s journey this year. His relationship as this other person. Batman is coming. Absolutely."
This will be really exciting for fans, as the caped crusader was never thought to be a part of the show until the final episode, but seems we will get to see a new take on the origins of The Batman and the beginning of his quest to save Gotham.