Context: three girls have been summoned into a world called Cephiro, and are told they can't just go back home now.
{"isekai" kara kono "Sefiiro" ni "shoukan" sareta} mono wa mizukara no ishi dewa mou moto no sekai ewa modoren 『異世界』からこの『セフィーロ』に『召喚』された者は自らの意思ではもう元の世界へは戻れん
Someone [who] {has been "summoned" from "another world" into this "Cephiro"} can't any longer by [their] own will return to [their] former world.
