Tenri, Keima's childhood friend, has moved back next door to the Katsuragis. She happens to be host to the goddess Diana, who tells Keima about she and the other 5 Jupiter Sisters once sealed away the Ancient Demons of Hell, the Weiss. At the same time, the students of Maijima High School are excited because Kanon has made a rare appearance in the classroom for exams. However, Kanon is preoccupied with the girl inside the mirror named Apollo, as well as the fact that she is being watched.

The goddess Apollo makes her appearance, but she is immediately stabbed by Lune, leader of Vintage, an organization which seeks to restore the Ancient Demons.

A girl who hosts a goddess will remember everything that happened during her conquest. In other words, she will remember falling in love with Keima. Armed with that information, Keima attempts to walk home from school with all five potential hosts and increase their affection level.

During the simultaneous walk-home-from-school events, Keima is attacked by a wave of flying books. The books are being controlled by a small figure. Meanwhile, section chief Nora drops by the Katsuragi residence to see Elsie. It sounds like the Hell Bureau of Peace has issued an order to the loose soul team to search for residents of Heaven. Kanon\/Apollo is currently at the Katsuragi residence. Is this a coincidence?

With help from Vulcanus, the third goddess, the Ancient Demon blade in Kanon has been removed. However, she still remains unconscious. Keima must search for the remaining goddesses and restore their power, but one of the potential hosts approaches him first. Does Keima have a way to handle a heroine who doesn't follow the dating sim model?

Thanks to a convincing performance by Haqua, Keima successfully releases the fourth goddess, Mars. However, Shiori was unfortunate enough to witness Keima during his conquest, and the shock leaves her unable to write a novel for the Mai High Festival. Keima tries to help Shiori complete her story, but what will she write about?

The goddess search is going well, but the strain is too much for Keima and he falls ill. However, this is an opportunity the God of Conquest to trigger the sick visit event. Ayumi and Chihiro are the remaining candidates for the final goddess. However, Keima doesn't realize how difficult it is to conquer two friends at the same time.

The Loose Souls team section chiefs are holding their regular meeting in Hell. Haqua questions Bureau Chief Dokuro about the rumors she heard from Nora concerning goddesses and Vintage, but Dokuro rejects her claims. Unsatisfied with the response, Haqua prepares to leave hell. Back on Earth, four of the goddesses have assembled in an attempt to awaken Kanon and Apollo.

It's the night before the Mai High Festival. Keima and Chihiro are alone on the roof of the school. Chihiro seems confused by Keima's behavior, but he continues with his conquest. But as Keima makes his move, Chihiro says something unexpected.

The last goddess is inside Ayumi, but only two days remain. Keima has no choice but to drop Chihiro hard and switch over to Ayumi's route. However, Ayumi happens to be watching and she begins avoiding Keima, which disrupts his conquest. At the same time, Lune has come to the Mai High School with her Vintage underlings to hunt goddesses.

Haqua returns from Hell after learning that Maijima Bay's Point Rock is a gate between Earth and Old Hell. Vintage has imprisoned the goddesses in Point Rock. Soon, demons, goddesses, and humans will be engulfed in war. After Haqua helps to save Ayumi, Katsuragi is determined to conquer the final goddess, but he needs Chihiro's help to get the job done.

The goddesses have been assembled and they take wing to Point Rock. Haqua and the Loose Souls team squares off against Vintage. And the climax of the Mai High Festival awaits.