大千世界，位面交汇。 万族林立，群英荟萃。 一位位来自下位面的天之至尊，在这无尽世界，演绎着令人向往的传奇，追求着主宰之路。
小男孩叫波波,狗叫阿木狗. 有一次小男孩在买饮料的时候中奖了，所以就的到了一个礼物，那就是阿木狗。
故事以史上首个自律人型AI「Vivy」为主角，是以「歌声带给众人幸福」为使命的「歌姬」。某日自称来自100年后的AI「松本（マツモト）」突然出现，并表示自己将与Vivy共同修正历史、避免100年后人类与AI发生战争，使Vivy踏上破坏AI的旅途。
In the year 1524, the former Assassin Ezio Auditore retired to a villa in the countryside of Tuscany, with his wife Sofia and children Marcello and Flavia. While Ezio wrote in his study, Sofia asked him to watch Flavia while she and Marcello visit his sister Claudia. Shortly after, he left his study to tend their vineyards while Flavia played nearby the villa. In the midst of his harvest, he saw a stranger cloaked in black, talking to Flavia. Fearing the worst, Ezio hurriedly intercepted the stranger, though Flavia told him that she was no danger, as Ezio saw her necklace with the Assassin insignia...
