"My goal? To spend every day freely and happily with beautiful ladies!" ――In the world of "Celes-Curiel," "Summoners" who contract and bond with monsters are considered a rare profession. The story of a hero who built a path for humans and monsters to coexist has been passed down there. Meanwhile, Sera, a low-level spirit being chased by villains, meets a young summoner named Marco. Sera escaped the danger once, but when she fell into a pinch again, Marco manifested his true power! In fact, he was the legendary hero who saved the world...! Utilizing the skills granted by the Goddess, Marco continues his journey to save monster "big sisters." And what fate awaits him at the end of it all…? Isekai Reincarnation × Monster Girls × Harem… A classic fantasy packed with all the best elements, summoned right here!!