You really do have to start with season one, Matt -- the characters grow and develop important relationships, and most of them are very appealing with believable foibles. The writing is usually extremely good and it has a sophisticated, fairly dry wit. As a friend said, it's the only show on TV that could make a joke about Galileo that works.
The premise is that Neil Cafferty is a handsome, brilliant, debonair young world-class forger, art thief, and con man. Peter Burke is a top NYC FBI agent in the White Collar Crime division, who managed to catch Cafferty on a bond forgery case. When Cafferty escapes prison weeks before his time is up Burke is puzzled -- why would a smart man do that and risk four more years? Ah -- damn fool: For love.
Cafferty is a lonely romantic who needs desperately to have someone to trust, and he chases an elusive former 'love of his life' -- who may or may not feel the same way about him. Intrigued -- and impressed by Cafferty's genius as a con man -- Burke decides to take him out of prison and make him an FBI white collar criminal insider/consultant.
Over the first season we see that slowly, uneasily, Neil starts to trust Peter Burke; Burke becomes rather skeptically attached and gradually realizes this is a guy who could become an honest man... well... maybe not... but regardless, he is becoming a friend, which poses conflicts for both of them.
Tim Dekay as Burke is absolutely outstanding, he never hits a bad note. Matt Bomer as Cafferty is winsome, sly, and a basically kind, alienated man who is just too damn slick for his own good. Burke's wife is wonderful, all the character roles are pretty good. Diahann Carroll plays Neil's landlady -- the wealthy respectable widow of a successful con man from another era.
Each episode they take on some new kind of scam or white collar crime, from art forgery to insurance fraud, embezzlement, stock market scams, etc. that requires Neil and the FBI to accomodate to one another to resolve.