Boukyaku no Cradle

In 20XX, owing to the mounting international tension, a certain country passes a new law that mandates a special education program for adolescents of fifteen years and older. Oblivious to the impending war, Kazuki finds himself, along with others, shipped to a remote island named Yurikago—the "Cradle Island." There they undergo training, but all too soon everything comes to an abrupt end...

(Source: Iskultrip Scans)