Mack the Mouse is a sad field mouse. Each night before he goes to sleep, he sings a song that tells how he wishes he had a home where he could be safe and warm, especially in the winter. But alas, each morning there still was no place for him. One day, with nothing better to do, he follows Ryne and Carene as the children go to Farmer Chapman's orchard. Farmer Chapman has a special box, and the children hear him singing about all the interesting things that are in his box. Naturally, they want to know what is in the box and, disobeying Farmer Chapman not to open the box, they lose the key when it falls through a crack in Farmer Chapman's cabin. Mack was chased by a cat and found safety under Farmer Chapman's cabin. He wants to help the children, but the key is too heavy. Could he talk the cat into helping him? Could he ever have a cat for a friend or find a home where he would be safe?