Miss Mackle is getting married! But she didn't invite any of her students to the wedding. The kids don't understand it: a wedding is a time for families to be together, and they are Miss Mackle's Room 3B family-which is especially important because her father is in the military overseas, and he won't be home for the wedding. So Harry comes up with a plan to sneak his pals into the wedding ceremony and hide in the back. It seems like the kids are going to make a horrible mess of their teacher's wedding . . . until they find a way to save the day for all involved.