The daughter of happily itinerant parents gets a world-altering taste of settled life in this engagingly cast story. Having spent her entire life on the road, nine months in one place looks like prison to Hillary, but her parents have agreed to house-sit for a family on sabbatical. Treating the experience as a test of character imposed by unseen watchers, she abandons her usual self- imposed isolation and deliberately sets out to make connections in her new (and her 18th) school, agreeing to tutor Brian, a student with Attention Deficit Disorder, in math, joining the circle of class queen Serena, and forming an unexpectedly deep friendship with Cass, a thoughtful loner. Readers will see past her pretense that it’s all just role-playing to the lonely, sensitive child within, and will be further attracted by the quiet competence with which she faces each challenge, whether it be managing the family finances for her feckless parents or mending fences with a jealous classmate. The roots this new life strikes in Hillary are deep and quick, but Koss (The Trouble With Zinny Weston, 1998) gives the tale an unpredictable twist when Cass indignantly rejects her grandparents’ offer of a permanent home, then pays the price when she and her parents are suddenly forced to pull up stakes. Undercurrents of humor, and characters who seem typecast initially but develop surprising complexities, give this bittersweet tale unusual depth. (Fiction. 10-13)