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.
(..) What did we find down there? We found a solution, Connor, that can end this war once and for all. We know the machines use shortwave transmitters to communicate. Our Intel has located a hidden signal under the primary channel. It allows for direct control of the machines. Skynet's a machine, (..)2009 Terminator Salvation