The family's first home in Minnesota was made of sod.  But Pa builds a clean new house beside Plum Creek.  The money for materials will come from their first wheat harvest.  Then, just before the wheat is ready to harvest, a strange glittering cloud fills the sky, blocking out the sun.  Soon millions of grasshoppers cover the field and everything on the farm.  In a week's time, there is no wheat crop left at all.
 

(Taken from On the Banks of Plum Creek book cover.)