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…