In a dystopian society, humans are now born without being assigned to a specific gender even though they resemble archaic images of male and female. They acquire their official gender assignment after going through what is known as “completion.” Rain, a young student on a field trip to an aquarium, envies that the rare fish she encounters have the ability to decide with whom to mate in spite of their specific gender. This is a privilege Rain doesn’t have, preventing her from returning any affection her classmate Sky gives her.