Ten years ago, a mysterious spatial anomaly now known as "Heaven's Gate" appeared in South America, shortly followed by the opening of "Hell's Gate" in Tokyo altering the sky and wreaking havoc on the landscape. The real stars disappeared, replaced by false stars. During this time, people possessing various special abilities — called "Contractors" — emerged, each capable of different supernatural feats. Following the disastrous Heaven's War, the United States lost its dominant position as a superpower to a mysterious organization named the Syndicate. The story revolves around a Chinese contractor codenamed "Hei" as he undertakes various espionage and assassination missions in Tokyo.

Uta — the most beloved singer in the world. Her voice, which she sings with while concealing her true identity, has been described as “otherworldly.” She will appear in public for the first time at a live concert. As the venue fills with all kinds of Uta fans — excited pirates, the Navy watching closely, and the Straw Hats led by Luffy who simply came to enjoy her sonorous performance — the voice that the whole world has been waiting for is about to resound.

The battle rages on as Shirou continues to protect Sakura, now consumed by the darkness. He joins forces with Rin to end the Holy Grail War, while Illyasviel, who knows the truth behind it, confronts her fate. Amidst the chaos, Zouken plots to manipulate Sakura for his own desires. The final fight begins.