After the events on the Tuatha de Danaan, which concluded the original series, the show takes place approximately two months later. It follows Mithril, who inadvertently stumbles upon Amalgam, a secretive organization. This group has access to advanced technology capable of nullifying the Electronic Cloaking System (ECS) mode and the Black Technology used by Whispered individuals such as Kaname Chidori. Amalgam is like other intelligence agencies, and they have a keen interest in obtaining more advanced technology. If only Mithril had not abandoned Sousuke's mission to protect Chidori, Amalgam would not have gotten their hands on everything and made their plans work out. Fans of the series know that it is based on the FMP novel titled "The End of Day by Day."