Best friends and small quarrels are the subject of this mild short novel, covering familiar ground for the early chapter book readers. When Molly moves to a new neighborhood, she’s snubbed by Violet the bully, but becomes instant best friends with Albertina. The two embark on building a treehouse together, and Molly shares her secret fear of the dark. Albertina is exceedingly sunny, the perfect best friend, until she gives away Molly’s secret. At an age where even petty grievances are crushing blows, Molly is betrayed; the girls reunite when she accepts that best friends can make mistakes. The style is light and easy, the characters chummy and wholesome. Fowler (I’ll See You When the Moon Is Full, 1994, etc.) is lenient with the girls’ ages and abilities; their conversations lapse into stiff adultish expressions, and they construct the walls of the treehouse without supervision, yet Molly can’t sleep without a night-light. Still this is an amiable choice for transitional readers, with two-color illustrations to break up the text. (Fiction. 7-9)