While searching for a run-away cat the twins Riko and Rimu Mikogami find a strange device that transforms them into Kirumin. It also enables them to turn into real animals. Their older sister Nagisa soon joins them. Now the three have cute, funny and sometimes dangerous adventures.

Set in the year 2004, Binzume Yousei is a slice-of-life fairy tale that revolves around four fairies, each represented by four unique colors as seen with their magical bottle jars. These fairies are the extremely peppy Kururu, the reserved and feminine Chiriri, the samurai-loving tomboy Sarara, and the quiet yet quirky Hororo. Fascinated by the human world, these fairies arrived from the fairy world in hopes of participating in the annual traditions and overall way of human life. However, they have a very limited understanding of the human world. Luckily, they are befriended and guided by two humans—Sensei-san, a university student who they live with, and a first-grade girl they call Tama-chan, who is sometimes as naive as the fairies themselves. Though these bottle fairies have strange ideas and sometimes have difficulty understanding this new world, they try to make the most of the human experience in their own cute little ways.

One year ago, a UFO containing 150 aliens crash-landed off the shores of Kasai. Because no one could fix their ship, the Japanese Government decided to bestow upon them the designation DearS and make them into Japanese citizens, teaching them the language, customs, and culture of Japan. However, in order for them to become more familiar with human society, a home-stay program has been enacted to allow them to mingle with other humans. One misty morning, a truck carrying a capsule that housed one of these aliens ends up dropping it into the riverbank, releasing her from her confinement. She is eventually found by a high school student named Takeya Ikuhara, who saves her from being hit by a truck and takes pity on her, despite being extremely distrustful of their race and wanting nothing to do with them. Upon being named Ren, she imprints upon him as her Master and serves as his personal Slave, leaving him with a DearS who wants to remain with him no matter what and bringing his ordinary, alien-free days to an end.

Several hundred years in the future, the resources of the Earth runs out, and the progression of the human race has stagnated. The world is now divided into Units. A boy named Hajiki Sanada lives with his mother and sister in Unit 74, in a place called Night Town, in which all electricity is shut down at midnight. The key in this story is an object called the GAD. GADs have the ability to reconstruct materials while reacting to feelings of an organic life. The size and shape of the resulting product seem to be different depending on the kinds of feelings that the life possesses. When Hajiki comes in contact with one by accident, it transforms into a huge robot—a Tekkoudo, or Iron Giant—which Hajiki names Lightning. And soon he realizes that he isn't the only one with a Tekkoudo, and must find out how to deal with those others who he feels are the same as himself. (Source: ANN)