On her way to London with her brother Peregrine, Judith Taverner mistakenly stops in a town hosting a prize fight and has an unfortunate encounter with a man in a curricle. When the siblings reach town and call on their guardian, Lord Worth, they find that he is the man in the curricle. Their father mistakenly designated their guardian as the fifth Earl instead of his friend, the fourth, who has died.
Judith is headstrong and determined to make a splash in London society. Although Lord Worth gives them assistance with suggestions and introductions, he and Judith continue to clash. Judith’s cousin Bernard Taverner warns her that Lord Worth may have designs on her fortune, which is large enough in itself but even larger if something happens to her brother Perry. Then Perry is first challenged to a duel and later his carriage is attacked. Judith and Worth are getting along better, but does someone have designs against Perry?
Most of Heyer’s Regency romances tend to either be funny or have an element of mystery (although they all have amusing dialogue). Regency Buck is one of the latter, with an engaging heroine, a mysterious plot, and as usual, perfect period detail.