Two siblings were happy on Mt. Olympus, until they fell in love. Deimo's sister Venus got imprisoned in the Swamp of Death. To save Venus's life, he must find a human reincarnation so that they can continue their love.

In the near future, there are people with special power called Sevens. It seems like the country has maintained peace by a company called Sumeragi Group, but they are the one who captured the people with the special power by force and did inhumane experiments. Gunvolt, the main character who has the power of Sevens, used to be in Feather, a resistant group who fought against the Sumeragi Group. The story begins with meeting the heroine, Sian.

Mimu Emilton is a cute fourteen-year-old who has come to the annual Starland Festival to become an idol, just like her role model, Yuri. It is the most celebrated event on a united Earth, and Yuri, now the President of Earth, has encouraged people to join the ranks of Excellent Idols. Unfortunately for Mimu, she can never seem to make it to her audition on time, as misadventure after misadventure lands her in situations (usually involving undergarment exposure, I might add) that she escapes with the help of the current Excellent Idols, whom she befriends. Just as she makes her place on the stage and begins her audition, though, an unknown group of aliens kidnaps her and the Excellent Idols. It is only the beginning of a wild interdimensional goose-chase that places Mimu in the position to save the world, if only she can believe in herself.

Jouji Gouda is a new transfer student at Hakuryo High. He fell in love at first sight and boldly proposed to Akane Suzumiya, representative of his class, on his first day at the new school. Although Akane finds him very annoying, hot-blooded and simple-minded Jouji never gives up and would do anything to express his love towards Akane.