Curious about the reasons behind her best friend's breakup, the bold Eiya Arakawa orchestrates a meeting with the ex-couple. In a café rendezvous, Yuuga Oota challenges Eiya to decode the relationship dynamics of another pair, impressing him with her accuracy. This leads to a private encounter where Yuuga introduces her to SCM, a device capable of enslaving others through duels. Intrigued, Yuuga enlists Eiya to safeguard him in case he falls victim to the SCM's control. Initially reluctant, Eiya eventually agrees, driven by her own desires. As they delve deeper into this dangerous world, Eiya finds herself embroiled in a perilous game orchestrated by a mysterious organization set on amassing slaves.