Written by Heather Hartt-Sussman, Illustrated by Georgia Graham
In this third book of related titles, our protagonist must face one more hurdle in accepting his Nana's new "family." Nana's new husband Bob has a grandaughter named Hortense. They were friends last summer - but over the winter she's changed and the tentative friendship they shared seems a thing of the past.
At the cottage again for a summer holiday, the protagonist is horrified to discover that Hortense is no longer likely to enjoy climbling trees and running around. She's grown tall, wears skirts, and pins pictures of rock stars on her wall. Nana has deemed it "inappropriate" for them to share a room. All seems lost, until the two manage to find something to work towards together: a surprise birthday party for Nana.