If the girl you love is from the Moon… Which one of you is really the Lunatic? It’s never easy when a stranger moves into your house, but if you have to host a foreign exchange student, Feena Fam Earthlight would be almost the perfect choice. She’s smart, kind, generous and attractive, but the problem is that she’s the Sphere Kingdom’s princess, and tensions between Earth and our Lunar neighbors have been tense since the big war. So, you might forgive Asagiri Tatsuya for having some reservations, but since his father is the first assistant to the president, what better place to board the princess so she can learn more about Earth culture? And, as mentioned before, Feena is VERY attractive. Unfortunately, the course of true love doesn’t normally have to contend with either interplanetary diplomacy or Feena’s bizarre entourage of assistants. And then there’s the question of how the kids at Tatsuya’s school are going to react. Get ready to see stars as two teens from totally different worlds collide in Brighter Than the Dawning Blue!
Princess Feena descends from the Kingdom of Sphere and rents a room from a family on Earth, as she wants to learns Earth's culture.
Princess Feena enrolls in school, but she feels the students are intimidated by her when they find out she is a princess.
Princess Feena and Natsuki are paired together for the cooking contest that they entered.
When Princess Feena mistakes bugs for aliens, she ends up destroying the study room of the house.
Everyone goes on a vacation to the beach; they get stuck on a 'deserted' island and become castaways.
Tatsuya and Feena are starting to have feelings for each other. At the same time, a young girl named Wreath is sent by a mysterious person named Feyaka to stop Feena and Tatsuya from developing their relationship further.
Feena decides to move out of Tatsuya's house in order to perform her princess duties at the embassy. Later, Feena's fiancé arrives on Earth and Tatsuya must decide what happens concerning him and Feena.
Tatsuya and Feena have confessed their love to each other. Everyone except Karen accepts their relationship. Karen sets up a challenge which entails Tatsuya having to defeat Feena in a kendo match.
Tatsuya and Feena's relationship continues to grow stronger, and Karen informs the King of the Kingdom of Sphere about the situation. For her actions, Karen is arrested by the military for treason.
After Karen is arrested, Feena goes back to the moon alone in order to prevent anything worse from happening. While there, Feena's father is reminded about the controversial relationship he once had with Cephilia.
Karen and Tatsuya land on the Moon and are still being chased by guards of the palace. Meanwhile Jurgen accelerates things, and a war between the Earth and the Moon seems imminent.
With the help of Takano and Karen, Feena and Tatsuya manage to avert the impending war. Years later, Tatsuya and Feena marry, uniting the Earth and the Moon.