Tom Angleberger’s latest, loopiest middle-grade novel begins when M’Lady Luggertuck loosens her corset (it’s never been loosened before!), thereby setting off a chain of events in which all the strict rules of Smugwick Manor are abandoned. When, as a result of “the Loosening,” the precious family heirloom, the Luggertuck Lump (quite literally a lump), goes missing, the Luggertucks look for someone to blame. Is it Horton Halfpott, the good-natured but lowly kitchen boy who can’t tell a lie? Or one of the many colorful cast members in this silly romp of a mystery.