Kazuya Kagami wakes up in class from a bad dream to discover that he is inadvertently groping classmate Chisato Chikaishi's breasts. After escaping her wrath, Kazuya goes to the roof where he takes comfort in his mother's obi. Kazuya is attacked by a possessed wig and falls off the building, but is saved by his obi. From within the obi, a young girl, a tsukumogami, emerges. They are met by the host of the wig. The tsukumogami asks the host to sever their link with the wig, which the tsukumogami calls an amasogi or curse. However, the host and wig attack and the tsukumogami is forced to destroy the wig before disappearing. At home, Kazuya reflects on the day's events before falling asleep. After another nightmare, he wakes to find the tsukumogami in his bed. After avoiding a confrontation with Kazuya's possessive sister, the tsukumogami introduces herself as Kiriha and that she the tsukumogami of Kazuya's obi and that Kazuya is now her servant.

Kazuya and class rep Chisato find themselves trapped in the school library, and it's up to Kiriha's knowledge of spirits and the forms they take to get them out.

A towering priestess shows up looking for Kazuya, and the person who sent her has an offer he and Kiriha might not be able to refuse.

Kiriha is being battered by the water goddess Kukuri-hime's attacks, when a mysterious vision gives Kazuya advice on how he and the tsugumomo might manage to survive.

Now that Kazuya has accepted the duty of exorcising any supernatural trouble that crops up, it's up to Kiriha to whip him into shape.

When the entire school starts acting like characters from a dating sim, Kazuya and Kiriha are forced to find the amasogi responsible before the affected people do something they'll regret.

Kukuri and Kokuyou have nowhere to live, and almost no income. Kiriha forces Kukuri to visit a neighboring local god for a loan, but the collateral being demanded might cost the two of them much more than just money.

Kazuya takes Kiriha and Kokuri grocery shopping, and then Shirou finds his charisma boosted to uncontrollable levels by a cologne amasogi.

A mysterious phantom student is stalking Kazuya's school, and Kiriha says that there's no such thing as ghosts. That leaves only one explanation: another amasogi.

A malison cleanser who knew Kazuya's mother is unimpressed with his skills, and wants to strip of him of his duties. But after seeing how malison atonement impacts the people struck by it, does Kazuya even want to put up a fight?

The duel between Sunao and Kazuya begins. Can Kazuya and Kiriha manage to overcome Sunao's thirst for vengeance?

Kazuya's duel with Sunao concludes, with Kiriha and Kazuya dead set on proving that a tsugumomo who works together with their master is stronger than one that's just treated like a tool.

The OVA features six 'Slightly Ecchi episodes that can't be broadcast on TV'.

My Tsukumogami Master: It focuses on Kazuya's daily life with with Kiriha, from waking up to her naked in bed and taking a bath with her after school.

At the Public Bath: It focuses on the Kagami-family's trip to the public bath along with Chisato.

My Master: It focuses on Sunao and Kotetsu's time in the bath together.

Kokuyou's Repayment: It focuses on Kokuyou attempting to repay Kazuya for letting her into their household.

Last Fort: It focuses on the aftermath of Kazuya's battle with Sunao, with Kiriha and Kukuri taking care of the incapacitated Kazuya.

Erotic Deliberative Assembly: It focuses on Kazuya being interrogated by the girls after an erotic book is found in his possession.