When it was announced, Gotham was about a young Jim Gordon and his early years as a member of the GCPD, but now it appears the show has been overhauled to focus on a young Bruce Wayne and will be similar to Smallville.
“This is all of the classic Batman characters,” said Kevin Reilly, chairman for Fox, at a panel for the network during its Television Critics Association press tour. “It follows the arc of how they all became what they are. I’ve read the script and it’s really good. It’s going to be this operatic soap that has a slightly larger-than-life quality.”
Reilly also said that the show will follow these characters as them become the heroes or villains we know and love. Basically it’s Smallville, but in Gotham, and it will end almost exactly like Smallville, only Bruce Wayne will be in the cowl instead of Clark Kent becoming Superman.
Source: io9