Second grader Alfie Jakes' former best friend, Lulu, announces that she's hosting the best sleepover ever--and that she's only allowed to invite five girls, but there are thirteen in her class. Alfie desperately wants to go but is not sure she'll be invited because Lulu has made new friends this year. When Alfie sees a classmate crying in the girls' room, she realizes this party won't be fun for everyone. Can Alfie convince her used-to-be best friend that a party is better when everyone is invited?.