Penny Rooney has cystic fibrosis, which means she has to do breathing treatments to help her lungs work. Some days, it seems like her CF is the only thing Penny knows about herself for sure. From her point of view, everyone around her can make sense of their place in the world. So why can’t Penny even begin to write a poem about herself for school?

Then during spring break Penny spots something impossible in the creek behind her house: a dolphin, far from its home. Penny names the dolphin Rose and feels an immediate bond, since the dolphin is also sick. But as Penny’s CF worsens, she realizes that Rose needs to return to her pod to get better.

Will Penny be able to help guide Rose back to the ocean, even if it means losing her friend?