Papa, Mr. Morrison and Stacey make another trip to Vicksburg. On the way home in the dark and rain, what happens to Papa?

In the boys' room, at first Stacey will not say what happened but finally tells the other children that on the way back from Vicksburg, the back wheels fell off the wagon, probably a trick played by some boys he saw standing near it in town. Rather than unload everything, Stacey held the horse still while Mr. Morrison held up the back of the wagon and Papa attached the wheel.