Shall we date?: Lost Island

Somewhere in Japan… there is an island called Aoshima, which has a beautiful nature. You (a new researcher) come to the island to do energy research. However, a series of mysterious deaths has occurred since extra-hydrate, or XH, was found in the island. What’s going on in the island? What are other workers’ real identities? And their real purposes are…? Will you all be able to leave the island safely?