When a hole opened up in the world and monsters flooded out, humanity prepared for the demon lord Rukimedes' rise once again. However, even the gravity of this situation cannot impede the antics of straight man hero Alba Frühling and sadist soldier Ross. Ross, trapped within a plane between two worlds due to Januar Ein's magic, encounters the demon lord taking a nap and looking far too comfortable in his confinement. Simultaneously, Alba, once again in prison, has been sidelined in favor of his eccentric companion's hijinks. Although separated, Ross and Alba continue their attempts to prevent the demon lord's resurgence, but unbeknownst to them, a ghost from Ross' past may just threaten their quest's success.

Like many hardworking members of the workforce, Kuroto Nakano is perpetually stressed out by his job. Still, since he lives alone, he must carry on to sustain himself. Little do humans like Kuroto know, this stress takes the form of darkness residing within a person's body and will bring one's life to ruin. Fox deities can see this darkness and have the duty to save people before it is too late. To help rid Kuroto of his stress, Senko-san, an eight hundred-year-old foxgirl, volunteers to take care of him, and will do everything she can to ease the tension in his weary soul.

Mahiru Shirota firmly believes that simple is best and troublesome things should be avoided at all costs. It is troublesome to do nothing and regret it later—and this ideology has led the 15-year-old to pick up a stray cat on his way home from school. As he affectionately names the feline Kuro, little does he know that this chance meeting will spark an extraordinary change in his everyday life. One day, Mahiru returns home to find something quite strange: a mysterious young man he has never seen before. His subsequent panic results in the uninvited guest being exposed to sunlight and—much to Mahiru's shock—transforming into Kuro! Upon revealing himself as a mere lazy shut-in vampire, Kuro promises to leave once night falls. However, one disaster after another leads to Mahiru accidentally forming a contract with his new freeloader, dragging him into a life-threatening battle of supernatural servants and bloodthirsty beings that is anything but simple.

The Seto no Hanayome OVAs are new stand alone shorts with characters from the series and also two new ones. It is now the third year of school, San and Luna's dads are still being over protective. All the while Nagasumi has his hands full trying to keep everyone around him under control and rescuing damsels in distress. (Source: ANN)