Theplotoftheseriesrevolvesaroundthreeyōkai（妖怪）,Bem,BeraandBarro,whoarriveatalargecoastalcityandcomeacrossanevilatmosphere,whichwasbroughtaboutbyimmoralbehaviorbyhumansandmischiefcausedbymonstersandyōkai.Theythereforedecidetostayinthecity,fightingagainstothermonstersandyōkaiwhichattackhumans,makingafewfriendsintheway.Eventhoughthethreeyōkaiareoftenabusedbyotherhumanbeingsduetotheirappearance,theystillstriveinprotectingthehumanpopulaceofthecityfromothermonsters,onedayhopingtobecomehumanbeingsinreturnfortheirgoodactions.