Counterintelligence is the kind of work done by people who work for the government or law enforcement. It's about making sure that other countries or organizations don't get too much information about themselves, their plans, or their operations. Counterintelligence agents will look for people who may be working to get information and will work to stop them. They try to figure out if someone is acting as a spy, which means they are trying to steal information or do something else bad with it. Counterintelligence agents then try to stop those people before they can do any harm.