Harold and George's time-traveling Purple Potty lands them in an alternate universe where everything seems delightful, but evil lurks just beneath the surface, and leads to a battle between Captain Underpants and his own evil twin. The Eighth Epic Novel Interest Level: 3-6 Reading Level: 4.7 ATOS Book Level: 4.7 AR Interest Level: MG AR Points: 1 AR Quiz: 108880EN Reading Counts Level: 2.9 Reading Counts Points: 4 Lexile Measure: 850 Guided Reading Level: T.