Tying the Knot with an Amagami Sister manga volume 5 features story and art by Marcey Naito.

When Uryu happens to peek at Yae's drivers license and sees the name “Reiko Ichijoji” -- the same name as the girl he met many years ago -- he resolves to find his way to the bottom of this new mystery! But suddenly, Yae insists on going for a midnight stroll with her, him, her sisters, and her best friend Makoto! And Makoto isn't about to let him pull any funny business! But when Yae goes missing on Mt. Inari, can Makoto and Uryu work together to find her? And just who is “Reiko Ichijoji?!”