In the fourth season, Sisi challenges the best jockey in Bavaria to a grand horse race to save the family’s estate, Castle Possenhofen, after the death of her father. Back in her homeland, she comes across dark family secrets and ultimately must ask herself where she really feels at home.

侦探查理哈德森与他所谓的“训练有素的执法动物”德国牧羊犬雷克斯组队，他更喜欢与雷克斯组队，因为雷克斯说话不唠叨。