Ava, Becca, and Cat are inseparable best friends who dread spending a summer apart after eighth grade. Outgoing Ava is dragged to London for her dad's job, anxious Becca is sent to summer camp, and quiet Cat is left at home. Phones aren't allowed at Becca's camp, and Ava's parents restrict her use of devices, so the friends vow to stay in touch through letters and collect souvenirs of their experiences to compile into a joint scrapbook at the end of the summer. As the girls step out of their comfort zones--and out of the roles they each play in the trio--they find themselves and their friendship changing and growing.