The vast game of Social-Network Tag continues to unfold in the real world—and in the middle of it, Yuma visits the Kashiwagi residence to unravel the mysteries surrounding his past. As his memories begin flooding back, he is greeted by a familiar face—his twin brother, Ataru! But this heartfelt reunion is anything but as Ataru kicks off a violent battle with Yuma. Who will prevail in this deadly fight between long-lost siblings, and will Yuma be able to discover the secrets of the Kashiwagi clan and his own identity?