Mr. Hill of Hill's Tractor Sales is doing his best to sell a brand-new tractor to Micah's grandfather. He even wagers twenty jelly doughnuts that Granpappy's old tractor won't make it through haying season. As the days go by, Micah learns that the tractor is Granpappy's old friend, and as Granpappy says, "Friends don't let each other down."
