Phoebe is delighted at the opportunity to go to Brussels as companion to Sally, rather than be an unpaid governess to her sister Jane's unruly brood. Her hopes are dashed when Zachary, Earl of Wrekin, taking up a diplomatic post, says she is too young and refuses to escort her. She will be unable to control the rebellious Sally, who gets into more scrapes even before they leave London.

To Phoebe's relief, when she rescues Sally from a calamitous action, Zachary is persuaded to relent, though the company of Jane's overbearing husband and his unpleasant sisters on the journey is irritating to them all.

Then Napoleon escapes from Elba and everything is in turmoil for Phoebe.