The show follows the life of protagonist Michael Westen (Jeffrey Donovan), a covert operative who has been "burned" (identified as an unreliable or dangerous agent) and tries to find out why.
[1] With his assets frozen, he is unable to leave Miami and forced to live off any small investigative jobs he can find, with the help of his girlfriend Fiona Glenanne (Gabrielle Anwar) and his old military friend Sam Axe (Bruce Campbell), who briefly informed on him to the FBI.
[2] His return to Miami also reunites him with his mother Madeline Westen (Sharon Gless), who becomes an increasingly important part of Michael's life even as he tries to hide his activities from her.
[7] The fourth season introduced new regular character Jesse Porter (Coby Bell), a counterintelligence agent whom Michael unintentionally burns but later makes part of his team.
[37] Ben Shenkman ("Tom Strickler"), Moon Bloodgood ("Detective Paxson"), and Otto Sanchez ("Agent Diego Garza") appeared in recurring roles during the summer season.
[38][39] The winter season premiered on January 21, 2010, opening with the reunion of actors Tyne Daly and Sharon Gless nearly 14 years after they last teamed up as Cagney and Lacey.
[40] Recurring characters in the winter season include Chris Vance as Mason Gilroy, a spy handler known as a "puppetmaster" with whom Michael must work.
Coby Bell joined the cast as Jesse Porter, a counterintelligence expert who can easily assume cover identities and has a burning desire to catch criminals.