meth-e-meth

In the past, humans discovered weapons called Autoscrolls and developed Oath-Making, a technology that enables control over them. In present-day Japan, Autoscrolls are common, and Oath-Making has evolved into a formalized science. Kyouta Yuzuki, a high school student and member of the Oath Club, becomes involved in an incident after discovering an unknown scroll. As a result, the Oath-Heart implanted in him transforms his body into a new form.