La espada de Kuromori

When Kenny Blackwood arrives in Tokyo to spend the summer with his father, he is stunned to discover a destiny he had never dreamed of. He finds himself in the middle of a hidden war that is about to explode. Racing against an impossible deadline, Kenny must find the fabled Sword of Heaven and use it to prevent the disaster. But a host of terrifying monsters is out to destroy him, and success will come at a price. With clever, fearless, sarcastic Kiyomi at his side, Kenny must negotiate the worlds of modern and mythic Japan to find the lost sword, before it's too late.