Shin SOS Dai Tokyo Tankentai

新SOS大東京探検隊

While packing for a move, elementary school student Ryuuhei finds his father's old school notebook detailing a search for a treasure in Tokyo's vast network of underground passages. With his little brother tagging along, he and three friends from an online chat room gather and set out on a quest to find the treasure. What they discover instead is an entire underground community composed of assorte...