Like every other thirteen-year-old, Blue is struggling to become comfortable with her changing body. Unlike every other thirteen-year-old, she's also dealing with a life-threatening endocrine system, a super cute diabetic alert dog named Otis, and a pair of way too overprotective parents. On top of all that, she's still reeling from the recent death of her beloved, treasure-hunting-obsessed grandfather, who made her promise that she'd never stop looking for their family's mythical fortune.

Desperate to honor his legacy, Blue vows to spend every day of the summer searching the ocean for the treasure with Otis by her side. But then she's saddled with Jules, the spoiled thirteen-year-old daughter of a vacationing movie star, who refuses to leave her side. While Blue initially resents having to babysit this new intruder, the two soon become friends, especially once Jules proves she knows her way around an adventure or two.

With Jules and Otis by her side, will Blue learn how to get out of her own way, make new friends, and find a legendary treasure in the process? Or is she destined to be nothing more than "the girl with diabetes" forever?