Sixteen-year-old Frieder's plans for the summer are shattered when he fails two subjects. To be able to move up to the next year in the Autumn, he needs to resit his exams. So instead of going on holiday with his family, he now faces the daunting and boring prospect of staying at his grandparents' house, studying with his strict and formal step-grandfather. On the bright side, he'll spend time with his grandmother Nana, his sister Alma and his best friend Johann. And he meets Beate, the girl in the beautiful green swimsuit. . . The next few weeks will bring friendship, fear and first love - one grand summer that will change and shape his entire life.