Desperate to retrieve some dangerous stolen letters, Christabel Sims, the Marchioness of Haversham, needs Gavin Byrne's help to gain entry to the scandalous house party where the letters are hidden. Gavin agrees to help the lovely young widow on one condition: that she goes as his mistress. But when Byrne, the illegitimate son of the Prince of Wales, discovers that Christabel's mysterious letters involve the Prince, will he use them to wreak vengeance on the father who denied him? Or will he give them up to protect the woman he's discovered he loves?