The stranding has already... changed into captivity.

Vian, the one female among the Demon King's Four Heavenly Kings. Reize, a baggage-carrying village girl in the hero's party. The two of them are sucked into a warped space caused by battle between the hero's party and the Demon King's Four Heavenly Kings, and are transported to a remote isolated island in the open sea. Stranded due to a spatial accident... Vian judges that early resolution is impossible, so she plans to seduce Reize, make her her captive, and turn her into a slave to survive their island life. However, this scheme ends up bringing out Reize's "love that runs a bit too deep" side... On the remote isolated island in the open sea with no escape—a natural cage— The baggage-carrying girl, a living equipment ghost possessing all of the hero's party's gear, goes berserk!! Will Vian be able to keep her sanity!? The crisis of being stranded transforms into a crisis of being confined!!