Main story!
Uke being succubus and half human... He will turn to human only after he finds his soulmate.. which is Seme who's a human and childhood master where uke was working as gardener.. he finds uke being fucked by his uncle.. rescueses uke and promises him be his life partner
But uke erased his memory which actually didn't.. so later re-encounters and tells him to be his partner!!!!
Hajimari Wa Sayonara