The Mentalist follows Simon Baker as Patrick Jane, an independent consultant for the California Bureau of Investigation (CBI) based in Sacramento, California. Although not an officer of the law of any sort, he uses skills and knowledge from his former career as a successful psychic medium (this was a ruse; he does not believe anyone actually has psychic abilities) to help a team of CBI agents solve various crimes, with the hope of one day bringing his wife and daughter's murderer to justice.

Source: Wikipedia.org