The Mentalist of the title is Patrick Jane, a former showman who used his formidable powers of observation, intuition and hypnotic suggestion to pose as a physic. This all came crashing to a halt when he boasted on TV of having helped police search for an enigmatic serial killer known as Red John. In revenge, Red John murdered his family, leaving Patrick Jane a bitter and broken man.
In the series, Jane has joined the California Bureau of Investigation (a sort of small-scale version of the FBI for the State of California) as a consultant in order to work towards catching Red John. The new and cynical Jane has disavowed being psychic, but still uses his abilities to read witnesses, trick people into confessions, and totally infuriate the CBI staff he works with. By season 3, Jane has encountered Red John several times without getting much closer to catching him, although he now realises is very influential and well-connected, and it's still not clear if he has an agenda, or is just totally psychotic.
The team is led by Teresa Lisbon (Robin Tunney) with two experienced male agents called Kimball Cho and Wayne Rigsby. Grace Van Pelt is a newcomer who has gradually come into her own. Jane is played to excellent effect by Simon Baker, who keeps him interesting and watchable despite often being enigmatic, moody, and infuriating.
The usual episode sees the team being called to a murder scene that the local town police can't handle. Jane will appear to bumble around the edges, asking sharp questions and sarcastically dismissing the ideas of the professionals. Eventually, he will pull some trick that reveals the truth in an impressively clever way, although he often misjudges his cleverness and has to be rescued from an angry criminal by the team.
The idea of Cop-plus-specialist is not a new one (Bones, Castle, Cracker, etc), but The Mentalist has forged a unique identity for itself. It mixes some grim scenes with personal humour and some well played interactions between the characters. Jane and Lisbon are the central characters without the show revolving around them, as the other members of the team have come into their own, although Rigsby is probably still a bit stereotypical. Cho's gang background comes up here and there, although he spends most his time as a deadpan but effective interrogator. Van Pelt does a good job of bringing some colour to the team, and her romantic subplot with Rigsby takes a twist this season. However, the heart of the show is Jane helping and infuriating Lisbon, and she increasingly takes professional risks to keep his help for the team.
The end of season two saw a bizarre encounter between Jane and Red John, which leaves Jane with some enigmatic clues to follow. The mystery deepens through the season, as it come clear that Red John has sources in the CBI that let him follow events and sabotage investigations. One problem within the CBI is the arrival of LaRoche, and internal investigator who seems happy to accuse anyone of anything just to see how they react. The season conclusion is appropriately dramatic and does a good job of bringing much of the plot together while leaving plenty of further mysteries to be solved.
The Mentalist is very watchable, mainly because Simon Baker makes Jane a believably flawed but brilliant man. Individual episodes are always interesting and watchable, and the central mystery draws you to watch more.