 The story revolves around seven-year-old Barbro, who has a secret twin sister called Ylva-li, the only person in Barbro's life who likes her more than anything else, and who calls her Most Beloved Sister.Ylva-li is the queen of the golden hall which can be reached by crawling down a hole under the rose bush, Salikon.Barbro and Ylva-Li ride their horses and have adventures together.