Clarinda Middlewick's friendship with Sarah, an orphan heiress, is encouraged by her father, a wealthy merchant. He hopes to marry Clarinda into the gentry, but she rebels when he receives an offer from Lord Tarbuck, whose daughter is several years older than Clarinda. Her only refuge is her grandmother, who runs a guest house in Harrogate Spa, and with Sarah's help she escapes from her home. Held up by a highwayman, whose actions they find extremely odd, they are forced to aid him, and the girls find adventure before they can reach Harrogate.