The night before her doctor's appointment, five year old Sofia worries about the shot she knows she'll have to get. As she drifts off to sleep, Sofia finds herself on an adventure with a talking cat, who is eager to teach her the history and purpose of vaccines! Together, the pair sail across the ocean learning important lessons about vaccines at each stop they make. First, they meet a talking turtle named Mr. Shell, who was born before vaccines existed! Mr. Shell teaches Sofia the history of vaccines and what life was like without them. Then, they meet a group of talking sheep who protect each other by staying together in a herd. When Mr. Whiskers explains that the purpose of vaccines is not only to protect yourself, but to protect those around you, Sofia starts to understand why shots are so important. After thinking about her grandparents, who get sick so easily, and her baby sister, who is too young to get vaccines, Sofia resolves to get her shot in order to be brave and to protect others. By the end of the adventure, Sofia realizes the importance of getting vaccinated, and the next day she goes to the doctor's office prepared to get her shot!