Areas ~Sora ni Utsusu Kimi to no Sekai~

Yuuya and Konoka, his younger sister, live homeless due to various troubles. One day, Yuuya gets an illegal job to get out of homeless life. The job, however, fails and he is captured by the group. He is ready for death, but the boss of the group says, "I like smart boys. I wanna you to be mine."
Like this, Yuuya and Konoka are sent to an isolated island. "It's warm here! There's no cold wind!" The island is like a paradise under the clear sky and surrounded by beautiful sea. Yuuya and Konoka are ordered to live there and enter school nearby. Yuuya and Konoka's school life on the island now starts...