A lovely tribute to female friendship, with a time-travel twist. I enjoyed the way Sales balances the time-travel aspect with what is really a book about female relationships and about friendship more generally - what it means to be a friend, how relationships change, the ways that children hurt each other. Many of the characters are a bit one-note, including the foster parents and the mean girl characters, but Charlotte is wonderfully realistic and richly portrayed, particularly in the way she makes mistakes in her interactions with her peers. Some plot points come across as a bit too easy, but the longing at the heart of the novel, for Charlotte to find her true best friend, Kitty, is achingly real, and readers will be rooting for the impossible to happen. The resolution is remarkably straightforward and refreshingly doesn't involve science fiction at all. Young readers may wish Sales had spent a bit more time on Charlotte's adjustment to an entirely new era, but in the end, the quick pace and focused plot will keep them hooked on the main conflict, finding Kitty. An enjoyable piece of realistic fiction with a sci-fi hook.