The sequel to Return to Shironagasu Island. Ikeda Sen, a detective working in New York, is approached by a mysterious woman named Lila. At the same time, his client Walton entrusts Ikeda with a mysterious device. Meanwhile, Izumozaki Neneko, who has returned to her everyday life, discovers a decomposing corpse along the Horikawa River on her way to school. These two completely unrelated stories soon begin to strangely intersect...