Switzerland's most famous child heroine returns to save a little lynx and the wild Alpine nature. High in the mountains, Heidi lives with her grandfather. The girl loves all animals, so when one day she and her friend Peter find a little lynx trapped between rocks, they decide to help him. The animal requires treatment and needs to return to its wild family far in the mountains. Unbeknownst to her grandfather, Heidi, Peter and an irreplaceable St. Bernard dog take on a mission to save their little friend. However, things get complicated when a greedy businessman decides to build a sawmill in the mountains and sets traps for wild animals. Now Heidi and Peter must protect not only the lynx and his family, but also their village and the nature they love.