A urethra stone made of pearl is excreted from the captured albino alligator (now in the Tokyo Zoo) that was found in the labyrinth of tunnels under the reclaimed land beneath the SV2 hanger. With the stone being worth over ¥200,000,000, some of the mechanics try their luck to see if there are anymore albino alligators excreting the stones down there. They don't return and nobody is particularly happy about staging a rescue mission to find them, especially after what happened last time. Sakaki wants to seal the manhole up, but Asuma decides to help and ropes in most of Division 2 to help him. Meanwhile Matsui calls Gotoh to tell him Tadayama Fumihiro, the man who lived down there and occasionally stole food from the SV2, has escaped the mental institution he was in and is most likely headed back to the underground passages. This information comes a little to late for the team and they fall prey to most of his traps, causing Ota to accidentally shoot up most of their equipment. Will they ever get out of there alive?