Restaurant owners call a company, called "mystery diners", when/if they are suspicious about their employees. Sometimes they steal or treat customers badly etc... The company will set up surveillance cameras and use actors to help find evidence that the employees are doing these things, sometimes leading to them getting suspended, fired or sued.
Did You Know?
Episodes of this show end with firings the same way they do on The Apprentice. The fired individuals however are actual restaurant employees instead of individuals vying for a job. See more