Do not let a mop sit overnight in water. Fix things before they get too big for fixing. Custodial wisdom: Mattie Breen writes it all down. She has just one week to convince Uncle Potluck to take her on as his custodial apprentice at Mitchell P. Anderson Elementary School. One week until school starts and she has to be the new girl again. But if she can be Uncle Potluck’s apprentice, she'll have important work to do during lunch and recess. Work that will keep her safely away from the other fifth-graders. But when her custodial wisdom goes all wrong, Mattie's plan comes crashing down. And only then does she begin to see how one small, brave act can lead to a friend who is hound dog true.