Minato is a boy who stopped playing water polo due to a certain incident in the winter of his third middle school year. He picks the sport back up again with a new team when he starts in high school, but the fledgling team runs into many problems.

The story follows the sometimes happy, sometimes sad, and a tad stressful daily life of "some sort of small, cute creature" (Nanka Chiisakute Kawaii Yatsu) known as Chiikawa. Chiikawa enjoys delicious food with bees and rabbits, toils hard every day for the rewards of work, and still maintains a smile.

Chiikawa and friends set off on a whimsical summer adventure to a mysterious island said to hide a long-lost mermaid secret. What starts as a fun getaway quickly turns into a heartwarming journey filled with surprises, gentle thrills, and adorable chaos. With sparkling seas, strange legends, and unforgettable encounters, the trio learns about courage, friendship, and the magic hidden in small moments.

12-year-old Oriko Seki, who lost her parents in a car accident, ended up living in her grandmother's Onsen Ryokan "Haru no Ya." With the ghost "Uribou" cohabitating with her and all the other odds, she ended up training to be a young female innkeeper. At first, she didn't like the training, but gradually felt her admiration for her title and began to train seriously. Thus, the growth of the young warrior Oriko begins.