I think it's relatively clean. The obi (paper band) has a tear; please check the photos. Book Overview: In the spring of her fifth-grade year, Chisato is called out to the sea and makes a strange promise. A mermaid asks her to befriend her child, who will be transferring to her class. Just as promised, Natsu Umino arrives as a transfer student. Natsu quickly becomes popular, but she hasn't revealed her gender during her self-introduction. However, during cleaning time, Natsu speaks to Chisato and reveals a secret: she is a mermaid... This is a story of a mermaid child who comes ashore to decide her future, and a boy who protects his friend's secret.