Zaregoto, Book 1: The Kubikiri Cycle — Nisioisin

It's the vacation of a lifetime, a trip to a remote island filled with geniusesâ€"and murder.

On Wet Crow's Feather Island, a tiny speck in the Sea of Japan, lives Akagami Iria, the exiled daughter of a powerful family. Born into great wealth, she was a princess of the highest pedigreeâ€"until she was cut off by the leader of the Akagami Foundation. For the last five years, she's lived on Feather Island with her maids. But she hasn't been alone. She has invited the best minds Japan has to offer to come and stay with her.

And so nineteen-year-old college student Ii-chan and his best friend, computer genius Kunagisa Tomo, find themselves as Iria's guests at her elaborate mansion. Surrounded by fascinating womenâ€"a chef, a fortune-teller, a scholar, and an artist, not to mention his own friend Tomoâ€"Ii-chan is feeling a little overmatched intellectually. But the sudden discovery of a grisly murder sends the island into shock. And Ii-chan discovers that he does possess a bit of genius: the ability to discover what is real and what is fake . . . who is who they claim to beâ€"and who is a killer.