Rose Cutler defines herself by her exacting standards. As an anti-racist, Jewish secular feminist eco-warrior, she is convinced she knows the right way to do everything, including parent her six-year-old nephew Nathan. When Rose offers to look after him while his parents visit Mexico for a week, her brother and sister-in-law reluctantly agree, provided she understands the rules—routine, bedtime, homework—and doesn’t overstep. But when Rose’s Newfoundland attacks and kills a corgi at the park, Nathan starts acting barking, overeating, talking to himself. Rose mistakes this behavior as repressed grief over the corgi’s death, but Nathan insists he isn’t grieving, and the dog isn’t dead. Her soul leaped into his body, and now she’s living inside him. Now Rose must banish the corgi from her nephew before the week ends and his parents return to collect their child.