The third movie of a four-part finale of Tamayura.

Unusual things have been happening in Moominvalley. Moomin, Sniff and Mee leave for the Observatory on the Lonely Mountains to confirm the Muskrat's words: a comet is about to hit Moominvalley and destroy everything. On the way they meet Snufkin, the Hemulen and the Snorks and experience many adventures.

Sixteen-year-old Yuuki Hase finally finds the courage to speak to his crush and ask her if she wants to become friends. The object of his affection, Kaori Fujimiya, is a quiet and reserved girl who cuts herself off from everyone and does not spare him the same blunt rejection she gives everybody else. Some time after, Yuuki finds her eating lunch on the roof where she secludes herself during break. He decides to start meeting with Kaori every day in the hopes of beginning to understand her better. The more time they spend together, the more she begins to open up to him. However, nearing the end of the week, she starts to push him away once more. It is then revealed to him the reason for Kaori's cold front: at the end of the week, her memories of those close to her, excluding her family, are forgotten, as they are reset every Monday. The result of an accident in middle school, the once popular and kind Kaori is now unable to make friends in fear of hurting the people dear to her. Determined to become more than just one week friends, Yuuki asks her the exact same question each Monday: "Would you like to be friends?" Because he knows that deep down, Kaori wishes for that more than anything. [Written by MAL Rewrite]

Second Lieutenant Kei Agemaki, the son of a famous general, has hidden his extreme fear of paranormal beings all his life. However, when he and two others are reassigned to live and work with youkai in the Ministry of Spirit Affairs, he is brought face-to-face with his worst nightmare. Now with the help of the fox spirit Kushimatsu, he and his fellow officers must learn to work alongside youkai maidens—Zakuro, Susukihotaru, Hoozuki, and Bonbori—to solve paranormal cases. Set in the midst of an alternate version of Japanese Westernization, Otome Youkai Zakuro explores the clashes and unions that can occur when east meets west, local meets foreign, and women meet men. The unusual alliance of the youkai maidens and human officers must learn to work together in a world that is changing around them. [Written by MAL Rewrite]