Andy and Terry live in a 169-story treehouse. (It used to be a 156-story treehouse, but they've added 13 more stories.) It now has a kangaroo-riding range, a WHATEVER-WEATHER-YOU-WANT dome and a hall of funhouse mirrors - the perfect place to hide from the truancy officer who is trying to catch them and make them go to school!
Unfortunately, the hall of funhouse mirrors is also the place where their evil trouble-making twins, Anti-Andy, Terrible Terry and Junkyard Jill live in a doppelgänger mirror, and they take advantage of the confusion to escape and wreak havoc in the treehouse.
Can Andy, Terry, and Jill escape school, save the treehouse from the doppelgänger mirror gang AND get their book written on time?