Alors que ses amis sont tous rendus blancs, Katak, le jeune béluga, est petit et gris. Pour prouver sa maturité, il compte exaucer le dernier souhait de sa mamie souffrante qui est de retrouver son premier amour dans le nord, à la Grande Banquise.

All of his friends have turned white, as expected at their age, but young beluga Katak is still small and gray. To prove his maturity and grant his ailing grandmother’s last wish, Katak sets off on a perilous journey to the Great North.