Natsu da! Umi da! Arale da! Nanda?

Arale is at the seaside during the summer holidays. Suddenly, a water spirit appears to pick up Senbei and his friends. The beach opens up and they end up at the Dragon Palace. Mashirito is there and demands to see the princess. She refuses, so Midori is dressed up as a double. But before she can go into action, Arale also disguises herself and serves Mashirito.