Little Illya's life has gotten completely out of hand since the Kaleidostick Ruby granted her the powers of a magical girl. Now a regular beach trip is going to turn into another crazy mystery adventure that she and her friend Miyu will have to unravel.
After experiencing a bizarre dream, Madoka Kaname, a kind 14-year-old girl, encounters a magical creature named Kyube. Madoka and her friend Sayaka Miki are offered the opportunity of gaining magical powers if they agree to make a contract with the strange little being. He will also grant them one wish, but in exchange they shall risk their lives by accepting the responsibility of fighting witches. Invisible to human eyes, witches are catalysts of despair in the areas they inhabit. An ally of Kyube, a magical girl named Mami Tomoe, befriends and encourages the two girls to accept the contract. For an unknown reason, another magical girl named Homura Akemi is determined to prevent Madoka from accepting the deal.
Minato Sahashi is extremely intelligent, yet due to his inability to cope under pressure has failed the college entrance exam twice. As a result he has been branded an idiot and loser by many. One day after talking to his yet again disappointed mother he comes into contact with a girl named Musubi who was under attack. The girl runs but takes him with her and soon finds that Minato, while unknown to him, is an Ashikabi, one of the mysterious set of masters that have the genetic trait that can become partners with some of the 108 cute girls, buxom women, and bishōnen called "Sekirei". The reason for the partnership allows the Sekirei to use all their power to win in the competition held by the mysterious MBI corporation.
The battle to find the supreme Sekirei continues. Still some of the fighters and their masters refuse to participate in the battle since losing it means to lose the Sekirei forever, and many of them actually care about their partners, while others just use them as tools. A storm is rising on the horizon, a bigger threat approaches the city and it's about to bring pain and suffering to those who love and care for their Sekireis.
Kasuga Arata lived a normal life together with his childhood friend, Hijiri Kasuga, in a small town. However, everything changed on the day of the Black Sun, and a magus (mage) appeared before him. The Black Sun caused the Breakdown Phenomenon which destroyed the town where he lives. Because of this, his normal life was artificially reconstructed by a grimoire that his childhood friend had left. The appearance of the magus led him to a new life in the Royal Biblia Academy and meeting the members of the Trinity Seven.