It is February 1963, and London is enduring the coldest winter anyone can remember. Ivy Brown, typist at the Wiseman Pulverizer Company, is about to turn thirty. As she sits, staring at the back of the typist in front of her and trying to avoid thinking about her impending birthday, two things lift her from her gloom: her brand new Beaver Lamb coat and thoughts of Arthur...

Arthur is the man on whom Ivy has pinned all her hopes. 'We are our own secret' Arthur says, and Ivy loves to repeat it. But when Ivy discovers that Arthur is a man who has many secrets, her determination to uncover the truth comes to spell disaster for all those in her way.