Heidi lives with her grandfather, in a cottage in the mountains. She receives an unexpected invitation from her friend Clara to spend the summer with her and her dad at the Baltic Sea. However, everything changes when she finds an injured lynx kitten and decides to nurse him back to health. The young lynx desperately needs to return to its family in the mountains! Without her grandfather knowing, she and Peter take it upon themselves to save their new little friend. Things get complicated when a greedy businessman named Schnaittinger wants to build a large sawmill in the mountains sets traps for the lynx. Now, it’s up to Heidi and her best friend Peter to protect not only the lynx and its family but also their village and the nature they love.