Azuki, the Toki-girl, and Shota, the Sparrow-boy, are home with their new-found uncle as their guardian. Azuki loves her incredible new loom. She’s saving feathers hoping for a better way to use them in fabric. Sewing them on just doesn’t work. It’s too bad she isn’t feeling well. She wonders what’s missing in her life.
Shota’s busy with the traditional boys’ school, his sailing lessons, and Uncle’s new school for girls and boys. His only worry is that the Dragon Princess, Renko, isn’t paying him much attention.
When Uncle discovers Azuki isn’t well, Shota decides the Crane-girl can help her. Disobedient, he sets off to find her, but returns defeated. Nobody he’s talked to could help. Even the news that Red Wind is in foal to Blackie doesn’t cheer him up.
Azuki finishes the fabrics and garments she promised and it’s time for Shota to set sail and deliver them.
Then Tsuruko, the Crane-woman arrives. She got Shota’s message and can tell Azuki what’s making her ill, but she is shy and sad. She decides to stay for now.
The Dragon King decides Renko must attend Uncle Yuta’s school to learn to be human. Renko worries: her father wants her to live as a girl, but her mother wants her to be a full-time dragon.
She’s happy to practice calligraphy but sad because she and Shota can’t fly together: they’re the wrong sizes. Renko can’t even tell him how proud she is of him. Yuta-Sensei forbids it.
Shota sets sail with his master, Minoru. In the Shimonoseki Straits, he sees many ocean-going western steam ships. Minoru predicts trouble: the foreigners think they should control the straits; the Japanese naturally disagree.
As they emerge from the Straits, Shota sees a monstrous waterborne army on the move. Minoru changes course but they are attacked by tentacled Umi-bozu. Shota is pulled overboard, but does the sensible thing and becomes a sparrow. He calls the Princess for help through his Wishing Rock.
Renko, Azuki and Tsuruko rush to help. Renko helps Minoru defeat the Umi-Bozu patrol while the birds assess the havoc they’ve wrought. Renko rejoins her friends, telling them her mother would be proud. A vast Dragon appears. Renko’s mother barely has time to look over Renko’s bird friends before she spots what she calls Kraken. Quickly, she deploys Renko and the others before attacking the Umi-bozu fleet herself. Tsuruko and Azuki round up the shipwrecked sailors while Renko, with Shota on board, blows approaching boats out of the way. Renko finally tells Shota how she feels, and their friendship is restored.
The Dragon King appears to see who makes a storm on his turf. He helps Renko organize the boats while Azuki and Tsuruko herd the swimmers towards them. The Dragon King leaves the mop-up to them and goes to assist the Dragon Queen. Together, they attack the Umi-Bozu.
The mother of the Umi-Bozu appears, begging them to stop, as Umi-Bozu have no quarrel with Dragons.
The Dragons have to admit their daughter is dual-natured The Dragon King proposes a meeting with Yuta via sound wave speech.
Yuta convinces the Dragons and the Umi-bozu to stop fighting with each other and let humans tackle their own problems, with the proviso that everyone will talk before fighting. The battle is over.
Renko hesitantly approaches her parents. They’re off to some big mountain, probably to talk about her, but as they leave, her mother tells her both her parents are proud of her, and her confidence is renewed.
Back at home, daily life resumes but Tsuruko has always had a mission and feels it’s time for her to leave. Renko has Wishing Rocks for all of them. Azuki realizes that they can’t split up. They must stay together, for they can help others and fulfill themselves. This is what she’s been missing.
They agree they will always stick together, as friends and to help others with their special powers.
Uncle Yuta knows his life won’t be easier, but he’s grateful for what his wards and their friends have accomplished.