Demon's Golden Thread

A seventeen years old Ryo Nagatsuka wandering through the night as he always does, until now. He encounter a mysterious white-haired girl named Anna, who has stole his heart. As he tried to know more about her, they were interrupted by a group of men in black, attempting to kidnap the girl Who is Anna exactly? What is the goal of these men in black? And more importantly—will Ryo able to get together with Anna in the end?