Richard Castle (Nathan Fillion)Richard Rick Castle is a best-selling author of mystery novels. This has made him very wealthy. He has, however, grown tired of his most famous character Derrick Storm and has decided to kill him and start fresh.When a killer begins to copycat the crimes from Castle's novels he is called upon New York homicide detective Kate Beckett to consult on the investigation. Castle's many years of research into crime in order to write his novels has actually made him an excellent detective in his own right with his own unique set of skills as a writer and observer. The two become partners and Castle also discovers the inspiration for his latest character Nikki Heat in Beckett.Although Castle is clearly useful on the cases he works with Beckett and other members of the 12th precinct he is also often a source of aggravation with his lighthearted nature, his tendency to overstep his bounds, and his general goofiness. For this he is both loved and tolerated by Beckett and her cohorts, who value his help over the exasperation he provides.Castle lives with his teenage daughter Alexis on whom he dotes and his mother Martha Hodges, a famous Broadway actress, who is both wise and a wiseacre.He possesses a roguish charm that is irresistible to the ladies but is not the most reliable romantic partner. Castle has been married several times.