Rosie Yates现在13岁了,家人们越来越难应付她的情绪和行为:她异常迷恋字母X、鼻子上有X的老虎、检票口和联邦快递卡车,会突然对自己和父母大发雷霆、拳打脚踢。 大家意识到,Rosie就像其他少女一样,只是在努力应对青春期的到来。就在一家人尽力应付成长为青少年的Rosie时,遗传学家打电话来,告诉他们Rosie病情的最新进展。The family struggles as Rosie hits puberty. She becomes erratic before, out of the blue, her genetic condition is diagnosed, and Si and Em come to terms with why Rosie is Rosie.