How will Petsy help?

In chapter 16, Mayhew helps clean up the kitchen while describing his plan. Even Mrs. Small becomes involved, asking to be a ghost in Mayhew's plan. Mayhew asks Thomas and his father to go to a theatrical store for him the next day while he arranges to have his father placed in the hospital to both trick the Darrows and to have his condition assessed by doctors. Mayhew then shows them the tunnel behind the mirror in the hall, suggesting this is how the Darrows have been gaining access to the house.