Gensou Mangekyou has returned!! Fifteen years since the first OP in 2010. As the 15th-anniversary work of Gensou Mangekyou, a brand-new episode, Chapter 19: "Gensokyo Time Operation Chapter (Part 1)," is here!! Summoned by Patchouli, Marisa arrives at the Scarlet Devil Mansion. Waiting there is a person far more unexpected than she could have imagined...! Marisa takes on a mystery that transcends time in this original Gensou Mangekyou story! Of course, those beloved characters make their appearance too! Who is this mysterious new character—unseen yet strangely familiar!?