Miyuki, a girl who has shut her heart to the world and hides in her shell, comes to a protectory that receives trouble-making children and helps them rehabilitate. One day, the dormitory matron, Mitsuyo adopts an abandoned dog and makes Miyuki take care of it. Miyuki and the dog - both in mistrust of people - are perplexed at first but slowly start to open their hearts to each other and eventually find each other irreplaceable.