Among the high rises of steel pipes, meshed power lines, and faded neon lights, exists a game that children dare to play within the ruins of the old city. "Otokoyo," a secret game of hide-and-seek, one where all who play wear fox masks and only begins when seven have gathered. But it is no normal game, as all who have played it have gone missing. Many whisper it is the work of demons, but that is just a rumor... or is it? Kakurenbo follows the story of seven children as they play Otokoyo for the first time and discover why if you play, you never return.

In the kingdom of Xoana, Lina Inverse and Gourry Gabriev unexpectedly come across their old companions, Zelgadis Graywords and Princess Ameilia Wil Tesla Saillune. Upon their reunion, the friends end up easily foiling the King of Xoana and his daughter's dastardly plans of world conquest. Soon after, it is revealed that Zelgadis is in search of the world's most valuable magical tome, the Claire Bible, hoping to discover a method to recover his human body among the many secrets sheltered within it. Despite his protests, the rest of the group decides to join in the quest after hearing of his mission. However, just when they were wondering where to start looking for the legendary book, they stumble upon a mysterious priest by the name of Xellos, who claims that he may be of some help in their pursuit. [Written by MAL Rewrite]

All hope seems lost when the world is suddenly invaded by aliens. Earth's only defense is a small three-person team known as the Special Counter-Aliens Task Force, consisting of an anonymous director, the tyrannical Shiro, and the easygoing Arikawa. The luck of the Task Force improves when Arikawa finds a teenage boy lying alone on a hill. The boy, Kakashi, is humanity's only hope—he has power previously unbeknownst capable of defeating the aliens! However, without any memories and with no knowledge on how to use his power, Kakashi is left clinging to Arikawa and Shiro as well as the only remnant of his previous life: his broken cellphone. Kakashi is conflicted by the fears and emotions clouding his mind and he calls his own motivations into question. Can he overcome his doubts and internal struggles and save the world? [Written by MAL Rewrite]

Based on the Korean drama television series about the love between two childhood friends and the tragic events that happen. In terms of the timeline of the Winter Sonata series, it belongs in the time gap midway through episode 21. (Source: Frostii Subs)