In the movie "Real Steel," Atom is not hiding a secret. He is a robot, and his capabilities are primarily determined by his programming and design. He is initially programmed to be a fighting machine, but he develops a unique bond with his trainer Charlie, which allows him to unlock his potential and become a champion.

It's possible that you are thinking of something else related to the movie, perhaps a specific scene or aspect you'd like to discuss. If you can provide more context, I might be able to help you further.