Dory, the youngest in her family, is a girl with a very active imagination, and she spends the summer playing with her imaginary friend, pretending to be a dog, battling monsters, and generally driving her family nuts.

Dory, a highly imaginative youngest child, makes a new friend at school but her brother and sister are sure Rosabelle is imaginary, just like all of Dory's other friends.

"Dory's sure that her big sister's friendship troubles have to do with pirates, but she'll have to navigate those rocky waters without her imaginary first mate Mary, who's found an exciting new pal of her own"--