Nanu the polar bear cub is worried. His ice slide is shrinking day by day. Mom and Grandma are worried about their home glacier-it's melting too. And Father Bear has been gone for days on a hunting trip.Driven by the melting ice floes, Mom and Nanu set out on a journey to find a new home. A friendly tern accompanies them as their pathfinder. But the journey is long and tiring, and ice is melting all around them. Will the polar bear family ever be reunited?