The episode beings showing Dr. D relaxing in a boat off the shores of the Palemden Islands within Imperial territory. His peace is abruptly disturbed by the Ultrasaurus, which erupts out of the ocean, nearly toppling his boat into the water.
The gigantic fortress-Zoid is docked at a base, and worker crews assigned to make repairs. Herman and Homalef see off Krueger, who is taken aboard the President's Hammer Head in order to be transported to receive better hospital care. The two shake hands, and Homalef joins Krueger on the Hammer Head. Herman asks Dr. D how long it will take for the Gravity Cannon to arrive--Dr. D surprises him, saying that everything he's looking at now is in fact, the Cannon. The Ultrasaurus had been parked alongside the massive weapon all along. Up on a platform overlooking the cannon, Van and company marvel at its size.
On one of the other islands in the vicinity, Hiltz, waiting in his Death Stinger, talks to some of his surviving Sinker pilots. He instructs the unit to search the islands until the Ultrasaurus is found.
Back at the dock, Dr. D gives a debriefing on the operation of the Gravity Cannon. The barrel of the Cannon will be mounted on the Ultrasaurus' left flank, and the power generator (also serving as the control center) on the right. He goes on to explain the mechanics of the weapon: the Gravity Cannon fires a special shell made of planacelitite, a material so heavy that it possesses its own gravitational pull. When the shell is fired, external pressure is applied, which magnifies the gravitational pull, creating a black hole contained within a special energy sphere. Everything inside the sphere is subject to be crushed by the force of the black hole. He ends the explanation, only to realize that he has succeeded only in confusing everyone. Herman speaks up, saying that it doesn't matter if they understand Dr. D's theory, as long as they can deliver the shell on target. He then puts Schubaltz in charge of aiming and firing the Cannon, calling him the best man for the job. Dr. D then reminds them that he only managed to make three Cannon shells, one of which will have to be used for a test run--in conclusion, they only have two shots left over for combat. Camford gives her approval to run a test, and Rudolph asks if he can watch.
Hiltz's Sinker unit is still patrolling the skies.
Herman oversees the process, while Van, Irvine, and Thomas take a nap. He gets a transmission from Dr. D, who confirms that the system check is complete. On queue, Van, Irvine, and Thomas wake up. Herman orders them to take their positions for the test.
Far away, Raven fills a jug of water and returns to Rease, who is resting in what appears to be an old, abandoned building. Raven apologizes to Rease, saying that her Geno Saurer wasn't able to be salvaged, as she recalls the previous incident; Hiltz firing the Death Stinger's Charged Particle Cannon straight towards her. Specula joins them, and Rease condemns Hiltz.
Back in the Palemden Islands, the Ultrasaurus prepares to fire the Gravity Cannon test run. Van in a Pteras, and Thomas and Irvine in Hammer Heads stay on the lookout, switching to combat status on Herman's command. Herman then contacts Schubaltz, who has taken his position in the Cannon's control center. The generator is pushed to maximum output, the shell loaded, and coordinates set. Schubaltz fires on Herman's command.
The test works perfectly; and everyone watches the power of the black hole as it penetrates the sea floor, sucking all the water away and creating a temporary crater in the ocean. Schubaltz wants to check the targeting, and figures out that the shot drifted 0.1123 degrees northwest. However, he knows the problem can be easily corrected and reports back to Herman, saying the test firing was a success. Everyone aboard the Ultrasaurus celebrates.
Their joy is short-lived, as the sound from the shot soon draws Hiltz's Sinkers. The Sinkers drop low, almost to the water's surface, ready to start their torpedo runs. Van, Irvine, and Thomas manage to take out most of the Sinkers with their Zoids. Torpedoes approach from underwater, but Thomas and Irvine counter, launching missile of their own. The four remaining Sinkers are defeated, but two stray missiles are aimed towards the Ultrasaurus. Van is luckily able to detonate them before they hit the ship.
Rudolph heads off for the Empire again, piloting a Redler marked with the Guylos insignia. He is escorted by two Black Redlers, flanking him on either side, which take off from the Ultrasaurus, brining the episode to a close.
- Death Stinger
- Blade Liger
- Lightning Saix
- Geno Breaker
- Hammer Head
- In the previous installment, Karl Schubaltz did the preview for this episode. This is the only time Schubaltz ever makes the announcement throughout the entire Chaotic Century and Guardian Force series.
- When Raven makes his appearance in this episode, one of the shots showing a close up of his face incorrectly portrays his facial marking. The dot that accompanies the strike across his right cheek is missing.
- It is clear in this episode that Thomas' AI system, BEEK, is able to be portably transported from Zoid to Zoid. While fighting in the Hammer Head, Thomas communicated with BEEK several times. BEEK was capable of operating the Hammer Head as it does the Dibison, launching missiles on Thomas' orders.
- Irvine uses an actual naval phrase in this episode, saying "We got fish in the water," referring to the torpedoes headed for the Ultrasaurus.
- The Geno Breaker is seen with both its X-breakers, despite them being previously lost during the battle against Van's Blade Liger and Hiltz's Death Stinger.
See also: Zoids: Guardian Force