Secretly in love with Riku Rei, the most popular girl of his school, Riku Suigin is forced to dive in "Grave Buster", the new virtual game where Riku Rei has been kidnapped.

To save her, he will have the support of the beautiful Twin Star and in addition to that he has inherited a 10 billion of yen charged device by his grandfather Riku Yuuki.

Suigin will have to become the last Guardian who protects the Tomb from the Raiders in order to save Riku Rei and solve the mysteries of Grave Buster.