Inukami! revolves around Keita Kawahira, a descendant of a Inukami-tamer clan and considered a failure by the clan due to his attitude towards his duty. Inukami, literally "dog god", are benevolent creatures that possess spiritual powers. They are a type of demon with the appearance of a dog who can transform into human form. Along with a partner from the historic Inukami-tamer clan, they act to obliterate evil and proliferate righteousness. Keita is initially unable to find an Inukami to bond with, but eventually a beautiful Inukami named Yoko decides to become his Inukami, causing Keita to become overjoyed. However, his joy is short-lived when he discovers that she is a very problematic and uncontrollable Inukami. From then on, Keita's life becomes filled with never-ending embarrassment.
The word inukami (いぬかみ) appears to be a corruption of the word inugami (いぬがみ), a type of Japanese spirit that literally means "dog god". The only difference between the two words is the lack of a dakuten in "inukami". A possible reason is that traditional inugami are considered dangerous spirits, more likely to cause harm than help, and are sometimes used to invoke deadly curses.