The Strait Jacket OVA is a "gun action fantasy" anime, set in a world where magic and technology exist side by side. Both sciences are used in the fields of medicine, warfare and research, but with differing results. Overuse of magic is forbidden as it causes mutations which transform the user into violent, uncontrollable and unstoppable monsters. These once-human "Malevolents" thus become the biggest threat to mandkind. Reiot Steinberg is a lone wolf "tactical sorcerer" dedicated to destroying these demons. Armoured and plated in his metal "mold", a straight jacket designed to keep him human, he walks a fine line between magic and madness as a rogue monster killer.