As Saki's group continues to make their way through the treacherous tunnels of Tokyo, they came across a underground river hidden within the caves. They split into two groups: One group with Satoru and Kiroumaru to drive away their pursuers and the other group with Saki and Inui to retrieve the submarine so that can continue their mission through the river. While making their way to the Psychobuster, they were attacked by a giant ragworm. Inui sacrifices his life so that Saki can continue with her mission. After retrieving the Psychobuster from an abandoned building, she take off towards the sun at daybreak. As she run pass the dilapidated scene of Tokyo, it reminisces her of the time with her last conversation with Shun. Then she saw an adult image of Shun right in front of her.
Il gruppo di Saki cerca di farsi strada nelle gallerie insidiose di Tokyo, finché giungono a un fiume sotterraneo nascosto all'interno delle grotte.
悪鬼を倒す唯一の手段であるサイコバスターを求め、東京にたどり着いた早季、覚、乾、奇狼丸の４人。そこは、想像以上に地獄の様相をていしていた。野狐丸の追跡をかわすために潜入した地下洞窟には、見たこともない奇怪な生物がうごめき、呪力を持つ早季たちですら対抗できない恐ろしい種も存在した。
それでも前進を続けていた一行だったが、やがて行く手を地下河川に遮られる。泳いで渡るのはあまりに危険な上、背後からは野狐丸も迫っているため、早季たちはふた手に別れ、一方がおとりに、もう一方が戻って潜水艇を取ってくるという作戦を立てる。
潜水艇に向かった早季と乾は、日暮れを迎えた頃ようやく隠し場所にたどり着いた。すぐさま潜水艇に乗り込み、洞窟に向かおうとした２人だったが、比較的穏やかだった昼とは違い、夜の海岸は恐ろしい生物の巣窟と化していた。
동굴 안의 위험하고 기묘한 생물들과 조우하며 가까스로 전진하던 사키 일행의 앞에 절벽과 지하계곡이 나타난다. 목적지에 도달하기 위해서는 원래 왔던 길을 돌아가 잠수정을 가져와야 하는데. 결국 기로마루와 사토루, 사키와 이누이 씨 조로 나뉘어 양동작전을 펼치게 된다.
不知何時洩露出的咒力，使東京的地下變成了地獄一般，為了躲避野狐丸等人的追捕，奇狼丸提議大家分頭行動，奇狼丸和覺負責在地下洞穴裡留下他們的氣味，而早季和乾先生則去開潛艇。但是開潛艇的過程並不順利，早季遭到了沙蠶的攻擊，幸好乾先生出手相助，潛艇才能繼續航行，在航行的過程中，早季再度陷入迷幻當中。
