UQ Holder volume 4 features story and art by Ken Akamatsu.

Tota meets Kirie Sakurame, a mysterious member of UQ Holder. Kirie looks like a little girl, but is apparently the wealthy patron of UQ Holder. Tota accompanies her on a trip to the tower to meet Karin (returning from the Moon), but the trip appears to have another purpose.

The powerful wizard Fate Averruncus, former ally of Tota's grandfather Negi, wants to take possession of Tota for reasons unknown. Despite having Karin, Ikku, Kirie, and Kuromaru with him, they stand little chance of stopping Fate, who possesses unfathomable power. Why does Fate want Tota? And can Kirie's secret plan succeed in stopping him?