When dorky, unpopular 11-year-old Otis wakes up in the morning at a sleepover birthday party, he’s in for a shock. At the marquee where the sleepover took place, it’s a scene of carnage and mayhem: there’s a donkey drinking at the chocolate fountain, five inexplicable traffic cones are dotted around the sleeping bags, a huge inflatable helium sausage looms above, one of the kids has a new tattoo, and there’s a suitcase of bratwurst on the floor. But neither Otis nor the other kids around him can remember what happened!  Did aliens abduct them and steal their memories? Or maybe they accidentally opened an interdimensional portal and let chaos through?