I will become your older sister. The reincarnated person from another world, Hinako, has formed a sisterly bond with the giant, Eiris, who was known as the "smallest giant." Together, they embark on a journey through this other world to find Hinako's "older sister," who likely also reincarnated, and Eiris's siblings. However, during the settlement of a certain request, they catch the attention of a knight from the church... "Ability (cheat)... Ah, regarding that matter, I must politely decline." A fantasy of reincarnation in another world, where a young lady and a giant search for their "precious people," begins to unfold.