Nine-year-old Alexander grows up in a small house with a small garden with his loving grandmother. On his tenth birthday, he promises her never to fall in love: He does not want to follow in his father’s footsteps and share his fate. Every Sunday, Alexander visits his father in the tunnel systems of the Vienna underground. As a young adult, he starts to care for his father and decides to be nearby. Alexander’s new workplace is a small lost-and-found office for the Vienna underground. Here he meets the beautiful and vivacious Caro. Alexander had already successfully resisted love two times before, now his promise will lead him into a bittersweet world and a fight between life and death – in which he will change the seasons from summer to winter.