It's a big week for the Quirks as twins Molly and Pen prepare for an exciting Halloween-inspired field trip to their local museum. Whichever fourth grade team creates the spookiest design wins an unusually fun prize. Meanwhile at home, everyone is ready for a visit from a certain Scottish guest: their Uncle Cork! He hasn't seen the twins since they were babies.At first, Uncle Cork seems totally normal, and Molly wonders if maybe she's not the only one in her family without a quirk. But then every time invisible Finn almost causes chaos, Uncle Cork is there to stop him. Molly can't believe it. It's like he has special vision or something....Black-and-white illustrations throughout capture the surprises, spooks, and nonstop laughs in this fourth Quirks book that proves every family is unique.