Quiet Graham Merrill (Bill Travers) finds his life suddenly turned upside down when a chance encounter of sorts finds him as the owner of an otter named Mij. Graham soon decides to move with Mij to the coast of Scotland, where they have more time together to frolic and play, along with exploring the beautiful scenery that surrounds them. While in this new town, Graham meets Mary (Virginia McKenna), the animal loving doctor. The two become fast friends, and along with Mij, they begin to embark on a series of adventures together. Will their time together bring new relationships and understandings of their surroundings and each other?