Raina wakes up with a terrible upset stomach. Her mom has one, too, so it's probably a bug. Raina returns to school, where she's dealing with the usual: friends, not-friends, and grades. It soon becomes clear that Raina's tummy trouble isn't going away... What's going on? A true story from the #1 New York Times bestselling, award-winning author of "Smile" and "Sisters"!