He's accused of having a 'hidden agenda'. [=a secret plan]
His suggestions have a 'hidden' [='secret'] purpose.
There was a 'hidden' flaw in the airplane's design.
(..) No. We'll protect her. She can learn to control it. I'm sure. Until then, we'll lock the gates. We'll reduce the staff. We will limit her contact with people and keep her powers hidden from everyone... including Anna. Elsa? Do you want to build a snowman? Come on let's go and play. (..)2013 Frozen