In 2003, author John Pearson interviews elderly John Burke (Sir Michael Gambon) and Susie Maxwell-Scott (Jane Lapotaire) for his book "The Gamblers," focusing on events surrounding the Clermont Club, a Mayfair casino run by ruthless zookeeper John Aspinall. The story centers around Lucan, 7th Earl of Lucan (Rory Kinnear), whose long losing streak leads him to gain custody of their children through manipulation by Aspinall and Veronica's husband, who protests at his profligacy. Lucan eventually kills Sandra, the nanny, under Aspinall's influence, but escapes in time to be taken to a hospital before he can kill his wife. Meanwhile, Dominic Elwes (Rupert Evans) writes an article exposing the Clermont Club members for their villainous acts and becomes a social pariah, committing suicide.
Lord Lucan, beset by marital and financial problems, attempts wife-murder. Bu...