Katak is a young beluga whale who lives with his family and friends in the Arctic. Although he is now as old as his white peers, he is still grey and a bit small. Determined to prove that he is as brave and strong as anyone else, he runs away to fulfil his grandmother’s last wish: to reach the Great North and discover the fate of his grandfather, who faced the terrible killer whale Machete. Thus begins Katak’s great adventure, a journey full of dangers and new friends, in which he will discover many things more important than the colour of his skin.