The game puts the player through a series of situations where they must answer various questions to progress.
In the small Nijiirochō in the Pacific Ocean, a crystal seal was scattered. Without this crystal, a devil would revive and destroy the world. Smashed into seven crystals, they somehow ended up with seven girls living in Nijiirochō. In order to reclaim the power of the crystal, the girls and "heart ties" are needed. The devil will be completely revived in six months. To save the world from ruin, a "player" that lives in Nijiirochō was chosen by Pixy for the task. Would the "player" be able to save the world?
In the arcade version, the seven main characters were named after candy companies that sponsored the game. When the game was ported, the characters were renamed.
- Megumi Moritsugu - originally named Megumi Morinaga in the arcade version. She is an innocent, bright, and friendly 16 years old girl. She is the first girl the player meets in the game, and the two often see each other in the street.
- Kumiko Shiozaki (潮崎 久美子 Shiozaki Kumiko) - originally named Kumiko Ezaki (江崎 久美子 Ezaki Kumiko). She is a 17 years old swimming Olympic strengthening player and a devoted sports girl who has visit the Nijiirochō swimming school since she was a baby.
- Momoko (藤倉 桃子 Fujikura Momoko) - originally named Momoko Fujiya (不二家 桃子 Fujiya Momoko). She is a bright 16 years old girl.
- Saki (想鐘 サキ Omokane Saki) - originally named Saki Kanebo (鐘紡 サキ Kanebō Saki) in the arcade version. She is a 16 years old girl who appears seemingly normal but is actually a serious person who serves the Earth Defense Force as an international civil servant. She is a member of the (rough translation) "International Defense Force Far Eastern Branch 3rd Military District 7th Division 11th Specialized Division Regiment Affiliation 3rd Mobile Guerilla Group" (国際防衛軍極東支部第3方面軍第7師団第11特課連隊所属第3機動遊撃班). During the events of the game, she is busy fighting everyday against a monster uproar in Nijiirochō.
- Mayumi Kobato (小鳩 真由美 Kobato Mayumi) - originally named Mayumi Tohato (東鳩 真由美 Tōhato Mayumi). She is a 25 years old naive teacher in the school the protagonist attends.
- Charlotte - Charlotte (シャーロット Shārotto, originally シャルロッテ Sharurotte) is a 12 years old girl living in the best mansion of Nijiirochō. She is the princess of a country that is exiled because of a coup d'état. She has grow up completely cut off from the outside world. Therefore, she is very selfish and egocentric.
- Emi Sakura (咲良 絵美 Sakura Emi) - originally named Emi Sakuma (佐久間 絵美 Sakuma Emi). She is a happy and cool 23 years old woman.
- Pixy (妖精 Yōsei) - She is a very optimistic pixie that encourages the player in his quest to save the world. She is voiced by Yuri Shiratori.
- Linz (リンツ Rintsu) - She is a familiar of the devil, a sassy 17 years old lady that appears in every place to get in the way of the protagonist by doing mischief. Despite being an enemy, she gets interested in the hero.