The Chief decides to give the main B.A.B.E.L. staff a company vacation at an outside onsen retreat in the mountains, and everything is running smoothly until Minamoto starts suspecting two foreigners due to suspicious circumstances after the chief's and Ichirō's yukata go missing. Minamoto and Shūji tail the blond man with sunglasses, while The Children secretly follow the foreign woman. The woman restrains Aoi and Shiho and incites a fight with Kaoru that ends after Minamoto interferes. The blond man reveals that he and the woman are special espers from Comerica, and are here to capture internationally-wanted criminal espers. Following this, the criminals are revealed, and the children help in their capture. The members of B.A.B.E.L. spend the rest of their vacation in leisure.
チルドレンへのごほうびとして桐壺局長が企画した「バベル・特務エスパー慰安旅行in山の奥温泉」が開催されることになった。チルドレンの３人を始め、賢木、ナオミ、ダブルフェイスなどなど、おなじみの特務エスパーたちが大集合、楽しい楽しい慰安旅行が始まった！！女湯ではオヤジモード全開ではしゃぐ薫。一方男湯では、桐壺＆谷崎のオヤジコンビの浴衣が盗難にあうという謎の事件が発生！！そんなマニアックな趣味を持つ犯人は一体誰なのか！？そして事件の背後に見え隠れする謎の外国人コンビ、サングラス男＆巨乳女の正体とは！？お約束満載の温泉編！乞うご期待！！
