Kumagami writes up a report on a computer about an embarrassing part of SV2 history. At an aquarium, a janitor cleans the habitat of Shiro the albino crocodile and discovers a gigantic pearl. TV news reports on the find, and the SV2 mechanics talk about how it’s the same crocodile that SV2 took on. The mechanics talk about the things they could buy if they had the money from selling the gigantic pearl, but Sakaki calls them morons and tells them that some things are best left alone. At night, mechanics Unoyama, Sasaki and Komatsuzaki break the seal on the hatch that leads into the underground dungeon. Division 2 and the mechanics gather around the hatch in the morning and find a note from the mechanics, stating that they’ve gone hunting for pearls. Sakaki orders his men to bring bags of cement out so they can seal the manhole cover and trap the mechanics underground. Shige pleads with Goto for help, but Goto tells him they had enough trouble last time they went down there. Shige pleads with the members of Division 2 to help, but only Asuma wants to help. He says their first mission ended in humiliation because they went in unprepared, but now they know what’s down there. Noa wonders what’s up with Asuma, but Ota doesn’t know. Asuma thinks it’ll be different this time because six people will be going down, but Goto asks what difference that will make. Goto gives his approval, and everyone gets ready with shotguns, flashlights and backpacks. At the same time, Sakaki starts mixing cement to seal the manhole cover. Inspector Matsui calls Goto to tell him about Fumihiro Tadayama, the dungeon thief. Tadayama was kept in a mental hospital since he had no family, but he recently escaped and wrote a message on the wall of his room vowing revenge.
The members of Division 2 head down into the sewer, with Asuma and Ota on point. Goto calls them with news that Tadayama escaped from the mental hospital and has probably come back to the dungeon. Shige tracks their movement and creates a map of the dungeon, and Goto asks Asuma to tilt his head and point the camera toward the ceiling, which is covered with incoherent messages in English. Asuma steps through a tripwire and causes strange figures to jump out of the water, which Ota starts shooting at. The shots ricochet all over the sewer walls, and they lose contact with the surface. The strange figures were made out of junk, and Asuma asks for a damage report. Kumagami has fainted, and they’ve lost their scanner, radio, camera and medical kit all because of Ota’s crazed shooting. Shinshi wants to go back to the surface, but Ota insists on going forward. Asuma points out that even if they wanted to escape, he doesn’t have a map of the way back because he hates mapping things. Shinshi steps in another trap and is flung up to the ceiling. Noa steps on a tripwire and causes part of the ceiling to cave in. The group is then locked inside the room filled with feral cats. After that, they trigger a trap filled with shooting arrows and an exploding bomb. Asuma doesn’t think the mechanics could’ve survived that, and Ota spots the door to Tadayama’s dungeon. They break in and find the three mechanics eating ramen with Tadayama, so Ota starts shooting at all of them until Asuma knocks him out. It turns out that Tadayama saved the mechanics and told them about all the hidden pearls. Asuma wants to keep going, but Noa says their mission was to find the mechanics. Asuma mentions that the pearls are each worth $2 million, so they could each buy lots of things they want with that money. Together, the members of Division 2, the mechanics and Tadayama search the sewer and find a room filled with pearls. They all start greedily scooping up the pearls, but Noa notices that they’re actually eggs – crocodile eggs. The eggs all start hatching and unleash tons of albino crocodiles. Three adult crocodiles then appear and start chasing everyone, and Noa says this is why she didn’t want to search for pearls. Asuma tells everyone to split up to lose the crocodiles, but they keep following him. They split down two paths that eventually re-merge, with the crocodiles still in pursuit. Asuma grabs hold of a pipe after falling out of a tunnel, and everyone grabs onto him. The pipe starts to buckle from the weight, and the crocodiles wait below them with jaws open. The pipe breaks, causing everyone to fall into the water. However, they all manage to swim away. Kumagami completes her report inside the dungeon, where they’re still trapped, with crocodiles banging on the door.
This crazy installment is a sequel to episode 38 of the TV series, where the members of Division 2 went underground to investigate the theft of multiple items from the station house. Of course, that search was also a disaster and ended with them being chased around the sewers by an albino crocodile. Now they find themselves back underground when three mechanics go on a greedy quest to find large pearls. Technically, this shouldn’t be possible because last time the manhole was covered with concrete, but here it’s covered with a simple tape seal and a mound of dirt. This time, they find all sorts of weird traps and strangle ramblings in English. Things could’ve ended there, but Asuma’s greed leads them into a worse situation with three crocodiles. By the end, everyone is still trapped underground. Overall, an amusing episode and a nice opportunity to see Matsui return, even though it’s just for a brief cameo.