The theft of the Greater Grail from Fuyuki City leads to a splintered timeline in which the Great Holy Grail War is waged on an unprecedented scale.

Aya Asagiri is a middle school girl who has problems both at school with bullying and at home from physical abuse by her brother. While browsing online, a website pops up on her computer featuring a creepy looking person. This person appears to take pity on her, and announces that she has granted Asagiri magical powers.

Hida Kizuna possesses the HHG (Heart Hybrid Gear) ability, but it is not strong enough to make him particularly important. His older sister calls him to transfer to a strategic defense school, where many of the students (many of which are large-breasted girls) use their HHG abilities to fight invaders from another world while wearing extremely skimpy pilot outfits. Kizuna's fighting ability doesn't measure up, but his sister has another plan—apparently having erotic experiences with Kizuna will allow the girls to replenish their energy or power-up. It looks like his new school life is going to be full of embarrassment.

Saikano: The Last Love Song on This Little Planet. is a manga, anime, and OVA series by Shin Takahashi, creator of Iihito and Kimi no Kakera. Saikano was originally serialized in Shogakukan's Big Comic Spirits magazine. A live-action movie adaptation was released in Japan on January 28, 2006 with Aki Maeda starring as Chise. The Saikano manga and anime series has been licensed and is being distributed by Viz Media in English in North America. The anime series is distributed in the UK by Manga Entertainment. Although the city is not mentioned by name in the series, many of the locations used in Saikano can by all probability be found in Otaru-shi, west of Sapporo. The train station, "Hell Hill", the Asahi Observation Hill, the view over the harbor, and the school all have similar looking counterparts in the city of Otaru.