Sekirei are 108 beautiful ladies of unknown origin, who together with their Ashikabi (human partners), must battle with one another in order to determine who will ascend and claim the "prize." What is the larger purpose of this event? What are the plans of the event's overseer, the same individual who found these Sekirei and introduced them into society?
Enter Sasashi Minato, 19 years old and approaching his 2nd year as a ronin. He is about to give it all up and return home, when quite literally, Musubi falls into/onto his life. An extremely well endowed, energetic, simple and sweet girl in a short miko outfit. Suddenly he finds himself as an Ashikabi, living with a girl for the first time in his life. And this is just the start of his new crazy life, which at most times is more than the poor Minato can handle.