In the deep underground construction site for a geo front, Boxer and Bulldog labors break through a cavern wall and make a discovery. On the surface, a priest at a temple proclaims that a calamity will unfold. Two geo front workers complain about how their work is being held up by the discovery, so they’d be better off sealing the hole that leads to what’s been dubbed the “mysterious caverns at the heart of Tokyo Geo-City.” One of the employees thinks there could be an upside if the company wants to open the caves to tourists. A call then comes in that yet another cavern has been found at the lowest level. The construction site suffers multiple explosions, and Division 2 is deployed to the scene. Noa thinks the idea of an underground city sounds like something from an old sci-fi movie, and Asuma explains that it’s between 100 to 200 meters below ground, with several independent units creating a ring with a diameter of 40 kilometers. Noa jokes that the place probably has treasure and jokes, but Kanuka comments that ghosts don’t exist. The fire department lowers a Pyro-Buster labor into the central shaft. Goto reads a letter that states the invasion of holy ground won’t be allowed, and he concludes that one of the men who went underground isn’t an employee. Goto wondered why SV2 had been called since fires and rescues are usually handled by the fire department, and the supervisor explains that the terrorist smuggled a bomb down to the lowest level. If the bomb goes off, it’ll ruin the entire project. Goto asks about a spot on the map, and the supervisor explains that they found a large limestone cave. Goto then briefs everyone and tells them it’s a dangerous mission because they’re dealing with a live bomb. Ota criticizes Noa for being scared, but gets completely deflated when Kanuka announces that she’ll be piloting Unit 2. Ota asks what’s going on, and Goto explains that Kanuka has counter terrorism experience with the NYPD and is a bomb squad expert. Asuma adds that calm composure is needed to defuse a bomb, and Goto tells Noa that she’ll be under Kanuka’s command. Ota cries, and Units 1 and 2 are lowered into the shaft on a winch. Underground, the terrorist sets the timer on the bomb and drops it in the water inside the cave. Noa and Kanuka conduct a block-by-block search, but so far they find nothing. Kanuka tells Noa to take point as they head to the next block, and Noa stops when she hears the sound of a creature howling. Kanuka tells Noa that they aren’t in some Jules Verne story and they won’t find buried treasure or ancient mysteries. Noa spots one of the bombs and tries to walk over to it, but Kanuka stops her and points out a tripwire. In the control room, Ota complains that they should be trying to catch the perps. Kanuka uses the manipulator gloves for the delicate work of disarming the bomb while Noa watches her back. Kanuka reports to Goto that their job isn’t done until they catch the perp, and Goto leaves Asuma in charge. He asks Hiromi to come with him and tells Ota vaguely that they’re going for a stroll. Kanuka concludes that the terrorist must be in the cave at the very bottom, but Noa is reluctant to pursue, so Kanuka pulls rank. Noa sees tentacles come out from the water and cover Unit 2’s legs.
The terrorist leaves his custom labor and is immediately knocked out by Hiromi and arrested by Goto. Goto wants to have a look around and flinches when he steps on human bones. He scans the area with his flashlight and finds multiple skeletons in samurai armor, which he guesses are from the Tokugawa era. Noa fires wildly to try to hit the tentacles, but they pull Unit 2 underwater. The bomb then explodes behind Noa, sending her into the water. Elsewhere, Goto and Hiromi climb through a ladder from the cave that leads out to an old well in a temple. The priest tells them he was surprised and thought they were the return of the Dragon God. He explains that the region was once plagued by a cruel dragon that killed many samurai, until one day a holy man sealed the dragon inside the well. Goto concludes that the bones he saw were from the samurai who tried to fight the Dragon God. Asuma frantically calls Goto and reports that he can’t contact Noa or Kanuka. Ota yells that he should’ve gone down there, but Shinshi tells him to shut up. The terrorist then tells Goto that he planted two bombs. Goto says that the target must be the Tokyo Bay operations tower and explains that all the excavated Earth is transported through an underground tunnel and added as landfill for the Babylon Project, so an explosion there would open the tunnel to the sea and ruin the whole project. The terrorist is shocked that Goto figured out the plan, but Goto says it was a wild guess. Goto says the bomb must be at Jonantoki, and the terrorist tries to strangle him. Deep underground, Noa and Kanuka find themselves in a partially flooded tunnel. Kanuka reports that one of her leg stabilizers is trashed, and Noa says the animal might attack them again. She picks it up on her sensors, and Kanuka decides to fight it while Noa escapes. Kanuka insists that it’s an order, but Noa instead picks up Unit 2 and sticks it on an overhead conveyor track so they can escape. They ride the track away from the monster and head up the tunnel. They stop in a room filled with large fire extinguishers, and Noa picks up the monster again. The monster attacks, so Kanuka shoots it multiple times, but to no effect. Noa attacks the monster with the fire extinguisher and paralyzes it, allowing them to escape. The monster gives chase, so the Ingrams start climbing up. Noa discovers the bomb, but Kanuka says she can’t disarm it in the 18 minutes left on the timer. Unit 1 picks up the bomb and continues climbing with the monster in pursuit. They reach the surface, and Kanuka says she can’t forgive Noa for disobeying orders, but thanks her for saving her life. The monster comes out into the open, and Noa attacks with her revolver and stun stick. With less than 30 seconds left, Noa shoves the bomb into the monster’s mouth, but Unit 1’s hand gets stuck. Kanuka blows it off and runs over to a crane, which she uses to knock the monster into the ocean before it explodes. Later, Noa asks Kanuka what she put in her report, and Kanuka answers nothing, because no body was found, so no one would believe them. She thinks the monster is a descendant from the dragons of the middle ages that adapted to a subterranean environment. However, Noa wants to call it a giant monster, and Kanuka yells at her for pursuing juvenile fantasies. They then argue about how a dragon could survive from the middle ages, with Asuma, Ota, Hiromi and Shinshi eavesdropping. Asuma wonders what they’re talking about, and Goto says that maybe they saw a dragon. Asuma asks them what they saw, but they continue to argue about whether it was a giant monster or dragon.
This episode mixes two common Patlabor tropes: terrorist plots and monsters. We learn that Tokyo is developing a geo front under the surface, and the project in turn supplies earth for the Babylon Project. Naturally, that makes it a target for eco-terrorists. While that part is interesting, we’re instead stuck with yet another weird monster that’s running around and causing trouble. Naturally, sparks always fly when Noa is put under Kanuka’s command because their personalities clash so much, and we definitely see that here. However, overall this episode just wasn’t very interesting.