Reborn Island ~Cuckold Play and the Shape of Love

One day, an island suddenly appeared in the sea, about 100 kilometers east of the Kingdom of Greatland. The island suddenly appeared where nothing was supposed to happen. Some people go to the island on orders from the government, some people go to investigate.
On the island, which is quickly becoming crowded with people, a boy wakes up. This boy, Rikku, has ...... amnesia.
Rikku wanders around the island not knowing what to expect. He meets Sienna Clark, a sister-student, and Mira, a self-proclaimed archaeologist. One of them looks out for him, the other out of curiosity.
Thus, a team is formed to explore each other's secrets and the island.
The three of them face one difficulty after another. Will they resist or will they give up? An adventure begins in which everything depends on your choice!