While heading to school, Hiiro Ryuugasaki hears a strange voice emanating from his storage shed. Upon searching the area, he finds a smartphone with the popular digital card game "Shadowverse" already installed. Assuming his grandfather has finally decided to buy him a smartphone after countless requests, Hiiro finds nothing amiss. Later that day, Hiiro receives concerning news about his classmate, Mimori Amamiya. She has become yet another victim of Takuma Kibakura, a fellow Shadowverse player who bullies his opponents by seizing their phones after defeating them in battle. Determined to retrieve Mimori's smartphone, Hiiro enters an exciting new world filled with intense matches and fierce Shadowverse opponents—including the formidable Lucia Yonazuki.