A few belugas live in a protected area of the St. Lawrence River. One of them is Katak, a late bloomer who is teased by those around him because he is still small and gray, unlike his peers who have all turned white. To prove his maturity, Katak runs away to find his famously brave grandfather, who, legend has it, stood up to the cruel killer whale Jack-Knife! Katak believes he will find his grandfather in the North, on the Great Ice Floe.
On his journey, Katak experiences many incredible adventures and makes new friends who help him realize that his differences are what make him unique, and that sometimes, being brave means being yourself.