Most people, including the girl herself, would say that first year high school student Yamada is beautiful and perfect. Despite this, she is working towards a peculiar goal: to have sex with one hundred men by the end of high school. Trying to put some sense into her head, Yamada's best friend, Miharu Takeshita, points out a major flaw in that plan—she is completely inexperienced with men. However, the reason behind this is that Yamada thinks her lady parts look strange and believes others will judge her for it. As a result, Yamada decides that her first time must be with a fellow virgin, since they will not hurt or scare her. After a fateful encounter, she sets her sights on the shy and average Takashi Kosuda, an aspiring photographer with a heart of gold. With contending rivals for his affection and her own raging hormones, Yamada must find ways to seduce Kosuda and take his cherry. However, as she gets closer to Kosuda, she finds herself increasingly enjoying their time spent together. [Written by MAL Rewrite]

Yumekui Merry begins with Yumeji Fujiwara, a seemingly average high school student. But ten years ago, Yumeji gained the ability to see the dream auras of other people around him. This ability allows Yumeji to predict what type of dreams people are likely to have next. The dreams of others may not be a mystery to Yumeji, but his own dreams have recently left him puzzled. In dream after dream, Yumeji has been pursued by an army of cats lead by John Doe, who claims he needs Yumeji's body to enter the real world. These strange occurrences get stranger when Yumeji meets Nightmare Merry, a dream demon seeking to return to her own world. Using his powers, Yumeji decides to assist Merry in getting back home. But Merry's very presence in the real world means that the barrier separating dreams and reality has been broken, and not all of the dream demons intend to come to Earth peacefully...

The third season doesn`t have a particular story behind everything (like "Valkyrie Ghost" in the second season). It just tells 6 stories about the life of Kazuto & Co. with some additions: Raine and Chorus get a house on earth, the last three Valhalla princesses each get an episode, and in the last episode Kazuto and Valkyrie, who in the same episode managed to stay adult, >try< to marry again. (Source: ANN)

The story on Arcadia's mystery, on which the 13th television episode was based.