Yetis live in on the top of a mountain in the Himalayas, Nepal, above the clouds and hidden away from sight. Migo is a yeti who abides by the law of the ancient stones held by the Stonekeeper, the yetis' leader. Migo's father, Dorgle, projects himself through the air each morning to hit a gong with his head, believing this allows the sun to rise. While learning how to ring the gong, Migo is distracted by the Stonekeeper's daughter, Meechee, whom he loves, and misses the gong, landing outside the village. There, Migo witnesses a plane crash and finds a "smallfoot" (human), whom the yetis have taken for legend. Migo runs back to tell the villagers what he saw, but has no proof. The Stonekeeper banishes him from the village. Migo is suddenly visited by Gwangi, Kolka, and Fleem who bring him to the Smallfoot Evidentiary Society (S.E.S.), which is led by Meechee. She convinces Migo to be lowered below the clouds despite the stones telling them that there is nothing underneath. After some hesitation, Migo agrees to go, but his rope snaps and Migo falls, where he discovers land..
High up on a mountain peak surrounded by clouds, a secret Yeti society lives in peace and harmony. One day, a Yeti witnesses an airplane crash; Inside lies "Smallfoot", a legendary creature that will rock the society to its core.