Granny Jantzen lives with her three granddaughters Dick, Dalli and Angela on the small pony farm Immenhof in Northern Germany. Since the breeding of ponies isn′t profitable anymore, Granny Jantzen is struggling to keep the family property. During the summer break , young Ethelbert is spending his holiday with his cousins at Immenhof. While Angela has fallen in love with the wealthy land owner Jochen von Roth, Dick and Dalli have to put up with bigheaded urbanite Ethelbert.

The third form of a boarding school and the students of a neighboring school do not get along. Each side dreams up the craziest pranks to defeat the other. And when one day the high school students go as far as stealing the Gymnasium students’ essays and even burning them, daily school life really gets out of hand.

The Immenhof has been closed by officials, awaiting auction. In the meantime, Angela has died, so Jochen is now a widower. Oma Jantzen and Angela's younger sisters Dick and Dalli live with him in the forester's house. In order to save the manor house, Dalli has started a "pony circus" with the village children in the barn, while Dick has given up hope of Ethelbert ever returning.