TWINS: Book 14: Envy... In this exciting addition to the 'Twins' series, Casey and Ali face more unexpected problems as Ali competes for Liam's attention. Neither of the girls ever anticipated the rift that develops or the envy that follows. For Ali, in particular, this is an emotion she is unfamiliar with. While Madison continues to cause havoc, the other girls attempt to ignore her but this proves to be very difficult especially when her annoying behavior leads to frightful circumstances that affect everyone at the camp. This is another great addition to the series and includes even more drama and suspense, a great book for girls 9-12 and beyond.