In a certain village, a rift connecting to the demon world opens, and monster flow out from within. As a skilled adventurer, the protagonist (you), “Zeno, the Wanderer of Archeological Ruins” makes his way to the site to resolve the issue at hand, but… encountering a Monster Girl Succubus, you are violated, your cumforce drained, and your level is returned allll the way back down to one.

Good thing the succubus has taken a liking to you (and your delicious cum). She proposes a deal: In exchange for your “Semen” she will offer you “Succubus Serum.” … … …A doping medicament with amazing power leveling potential… … … ???