Alma Tandoji, seventeen, keeps others at a distance due to a past incident. One night, Ruri Aiba appears at his door. She pleads with Alma to battle against the Dark Stone, creatures that can only be defeated by the power of the Sacred Seven within Alma.

Ruri is the new Chairperson of Almas academy, and calls him to her office to ask him again to join the battle against the Dark Stone. Meanwhile, a plane departs from a US military base, secretly carrying an extremely explosive material.

Ruri returns from London after buying a fine grade gemstone for Alma to use. During trip a routine trip home, she and her convoy is attacked by Knight, the one who caused the Darkstone incidents. Kenmi reveals his reasons of his research on the Sacred Seven and information on his history on Knight.

Ruri and Alma participate for the school fair. However, things turn worse when a few of Knight's Darkstone snakes cause problems. Wakana converses with Ruri to know her a little more.

Tandoji and the Geology Club went to a camp. There, Kagami and Tandoji found a darkstone and informed Ruri about it. They managed to defeat it without the geology club members knowing.

Ruri invites Alma to eat lunch with her. Alma feels very annoyed by Ruri. Knight kidnapped Ruri to get a serum that will help him control the darkstone in him.

Naito has escaped with Ruri, but the transmitter Kenmi placed reveals the possible location of Naitos hideout. Alma catches up to Kagami, who asks him to investigate the site. Alma searches for Ruri and runs into Naito, whos been waiting for him!

Almas relationship with Ruri causes him to be teased by his classmates, a sign that they have started to warm up to him. Gradually, Alma is finding his place at the academy. Almas still hesitant but Wakana is elated that people see him for who he is.

Theres been a change to Ruris sister, Aoi. Five years ago, as Ruris family, their butler Kagami and his son spend a fun-filled Christmas week together, Ruri and Aoi have a fight. While small in scale, it changes the destiny of the two girls.

Ruri was taken in to custody by Kenmi. Alma, Kagami and the entire Aiba Foundation declared war against Kenmi Group and rescued Ruri. Knight and Fei plans to use the vaccine on Zero to retain his mind and control over his Darkstone powers.

Kenmi's laughter echoes through the forest. Hes absorbed Number 0s energy and plans to consume Alma, who holds a purer power of the Sacred Seven. To stop Kenmi's ambition, Naito attacks. Their last battle surrounding the Sacred Seven has begun.