Thirteen-year-old Karin Hanazono feels like her life can't get any worse, Her parents died when she was younger, leaving her with an aunt who doesn't hesitate to call her stupid and useless over her poor grades. Her only friend, her cat named Shii-chan, passed away recently, leaving her completely alone. All she has left of her parents is a ring given to her by her mother, which she treasures dearly as the sole thing left of her past. Kamichama Karin begins the moment her life takes a turn for the better, when she is approached by Himeka Kuujou, a cute girl who has also lost her parents, and Kazune Kuujou, her cousin who finds girls to be troublesome, both of whom are searching for a goddess. Her mother's memento ring shines brightly in their presence and fills her with its radiance, making her smarter, faster, and capable of granting wishes. It turns out that her ring allows her to become the very goddess they were looking for, and now that she has awakened that power, others will come after her for it…

Katakura Kippei is in every way a high school playboy. Spending his days flirting with any female he can see, responsibility is the last thing on his mind. Life takes an unexpected turn for him as one day he returns home to find himself with the fulltime task of caring for his 5-year-old cousin. Kippei's aunt Miyako had disappeared, appearing to have abandoned his cousin, Yuzuyu. With Kippei's lack of responsibility and knowledge of childcare and Yuzuyu's injured heart with the disappearance of her mother, their time together is in for a bumpy ride.

In a futuristic society, Japan has implemented a complex system referred to as "The Red Threads of Science" to encourage successful marriages and combat increasingly low birthrates. Based on a compatibility calculation, young people at the age of 16 are assigned marriage partners by the government, with severe repercussions awaiting those who disobey the arrangement. For Yukari Nejima, a teen that considers himself average in every way, this system might be his best shot at living a fulfilling life. However, spurred by his infatuation for his classmate and long-time crush, Misaki Takasaki, Yukari defies the system and confesses his love. After some initial reluctance, Misaki reciprocates his feelings in a moment of passion. Unfortunately, before the two can further their relationship, Yukari receives his marriage notice. He is then thrown into a confusing web of love and lies when his less-than-thrilled assigned partner, Ririna Sanada, becomes fascinated with his illicit romance. [Written by MAL Rewrite]

Shiki Toono sustained a life threatening injury as a child, and due to that incident he was sent away from the Toono household and was given to a relative to be raised. Years later, when Shiki is in high school, the head of the Toono household—his father—dies, and he is ordered to move back in by his sister Akiha, who is the new head of the household. However, Shiki holds a huge secret. Ever since that injury, he has been seeing lines on objects, and only with a special pair of glasses is he able to stop seeing them. Also he is unable to remember anything well from the time before his accident. The day he moves back to the Toono household is the day he stumbles upon a woman named Arcueid Brunstud and decapitates her with one stab of his knife in a temporary fit of insanity. When she suddenly showed up beside him later alive and well, and ask him to be her bodyguard, Shiki's journey to unravel the mysteries of his past begins. (Source: ANN)