Sadao Maou, the Devil King, has finally been promoted to store manager! And who should move next door to his fortress (actually a tiny studio apartment in a dingy walk-up) but a lovely kimono-wearing lass. But the former devil-crushing hero Emi Yusa is none too pleased with this turn of events, to say nothing of high-schooler Chiho Sasaki, who's still nursing a terrible crush on the Devil King. Meanwhile, a Sentucky Fried Chicken has opened up right across the street from Sadao's beloved MgRonald! It's the first real test of his managerial prowess, and he's facing a pay cut unless he can top SFC's sales! Between the two new neighbors, the Devil King's troubles are anything but part-time!