"Birthdays are great. You get gifts, and cake, and sometimes a party. Shame the next birthday is your sister's! Say hello to twins Brin and Arlo, their stressed-out parents and their big sister Ellie. Ellie is about to be 13, which may be lucky for her ... or not. And Brin and Arlo have just discovered some interesting gifts of their own."--Back cover.
Writing a summary for young readers…
For young readers
Book data: Open Library