The cat that Olive rescues from a flood has a secret: he's not really a cat at all, but an alien who crashed to Earth on a beam of light. The cat, whom Olive names Leonard, was prepared to visit the planet as a human--but something went wrong. Now Leonard may never know what it's like to hold an umbrella, go bowling, or host a dinner party. (And his human jokes still need some work: Knock, knock. Who's there? Just Leonard. It is me.) While Olive worries about whether she will have to move after her mom and her new boyfriend get back from their summer vacation, Leonard tries to figure out how to get from South Carolina to Yellowstone National Park, because if he's not there at the end of the month, he'll miss his ride home. But as Olive teaches Leonard about the beautiful and confusing world of humans, he starts to realize how much he cares about this particular one. A sweet and dryly funny story about what it means to be human--and what it means to be home.