You, an explorer from the city, arrive at Shirokiba Island, a mysterious place rumored to be home to white tigers. This island has never been explored before, and you have come to study the wildlife population. After spending a full week researching, you decide it's time to go back. When your ship starts sailing without wind and a storm suddenly big waves hit your ship back to the island even though the water current is fine, you try again and again the waves push your ship back as if there was something blocking it from leaving. You decide once again to try sailing again and this time a bigger impact comes and throws you off the ship and falls unconscious. A few hours later you wake up in a place like a room in a castle, you hear a voice approaching

"Hey, you're awake... you want to go, huh? It's not that easy, darling"

You immediately turn around, only to find an extraordinarily beautiful girl standing before you—someone who seems to be from a world far different from yours.