|Season 3, Episode 6.5|
|Air date||July 6, 2008|
|Written by||Noboru Yamaguchi|
|Directed by||Yū Kō|
Futatsuki no Kishi - 3.6.5 Seductive Beach (OVA)
Princess no Rondo - 3.7 Slepnir Dance Party
Saito blinks as he looks at the contents of a secret box. Professor Osmond had asked Saito for confirmation about the chest's contents, and Saito confirms that the contents are indeed from Earth, but he has never found so much.
Instead of going to Romalia for summer vacation, everyone goes to the ocean instead this year. Louise is disappointed that Siesta has tagged along. Saito complains that the girls aren`t wearing real swimsuits and explained to Guiche what a real swimsuit is. To everyone's surprise, Queen Henrietta and Agnes come to enjoy the vacation. Professor Osmond asks all the girls to change into what is in the chest: swimming suits from Saito's world. Osmond says they are traditional uniforms for the ritual for the spirit of water and says nobody can jump in the water until everyone wears one. Osmond explains the first ritual: The girls must splash each other to cleanse one another in one-piece suits. Saito says there are more extreme garments in the chest.
The second ritual involves the girls changing again into two piece suits, this time, an offering ritual. A series of beach games follow, and Louise asks Saito to take her out on a midnight walk. Saito unexpectedly agrees to do so. The final ritual is a tournament: The winner can wear the true Priestess's garments, which scantily clad suits made of seashells and starfish, and the boys secretly make plans to make Tiffa win. Agnes yells at the referee (Guiche) because of unfair penalties. Later, Saito blows off Louise's walk on the beach. Louise discovers the boys plan.
Tomorrow morning, Montmorency says the finalists have a sudden problem and can't come. Montmorency also tells Saito to come to the far side of the beach. Saito is then tied up by the other girls. Osmond is then invited by Kirche, Maricone is then invited by Tiffa, then all the boys (Saito, Osmond, Guiche, Reynard, and Gimli) are tied up to a rock wearing the priestess's garments. The girls go back in the water to play, but they're ambushed by the Water Spirit (a Giant Octopus) that comes every 30 years. Or so Osmond says. Shortly afterwards, Saito breaks free and rescues the girls. Later, the girls try on the skimpy swimsuits out of curiosity, and Saito comes back to show Louise the food he is preparing, but inadvertently sees them, only to have Louise's top fall off in the commotion.