The wonder of Us by Kim Culbertson

Introverted history fanatic Abby has had it with feeling abandoned, what with Mom having left the family home and best friend Riya leaving their Californian hometown for Berlin. Moreover, she and Riya parted on bad terms and life hasn’t been the same since. But now, thanks to Riya’s grandmother, they have an opportunity to fix their fractured friendship during a two-week trip around Europe. Being chaperoned by Riya’s cousin is initially annoying, but he and Abby find themselves bonding while things run less smoothly for her and Riya. Matters come to a head in Edinburgh when Riya’s secret is revealed, and the eruptions they experience in Iceland aren’t only of a volcanic nature…