One day, a fox kit living in the Romus Forest contracts the apparently uncurable "Romus disease", leaving his mother distraught. She remembers her grandmother's story of a cure hidden deep within the forest, a piece of fried tofu found at a shrine. Both mother and son now set off to find the legendary remedy, braving predators and other hazards to save the kit's life.

Harry Fox won the Story Class prize in Micro Cabin's 1st Adventure Game Contest, and was marketed as a graphic text adventure for all audiences. It is separate from the later MSX remake, Harry Fox Special, forgoing RPG elements to focus on puzzles.