One day, Graham Merrill (Bill Travers) spots a frisky otter in a pet shop window. He impulsively brings the playful creature home and falls in love with him, but soon realizes that a cramped London bathtub is no place for such a creature. Tired of hectic, noisy city life, Graham decides to move to a small village in Scotland and fulfill his dream of being a writer. He and the otter explore the countryside and befriend Mary MacKenzie (Virginia McKenna), the kindly town doctor.