Botan Ichige has always dreamed of enjoying a tea party with angelic girls. When she enrolls at St. Asmaria All-Girls School alongside her best friend Shinobu Itoko, it begins to feel like her dream could become reality. Suddenly, an angel appears among them. Calling herself Un, the strange girl offers the duo her halo to eat. However, consuming the halo causes Botan and Shinobu to spontaneously "conceive" and "give birth" to colorful mushroom-shaped objects. Feeling unsettled by the lewd act she is forced to endure, Botan cheers up when Un says that her wish will come true if she can lay one hundred thousand "eggs." Spurred on by Un's words, Botan's struggles to achieve her dream have only just started.