The episode opens with a team of scientists exploring an ancient ship on the ocean floor. They are eventually taken by mysterious tentacles, and the opening credits roll. Afterward, H.E.A.T. is shown sailing toward a point of tachyon emission, where they discover the ship of another famous scientist. on board, it is revealed by the ship's captain that the scientists in question had been under the sea for three days, after which Zilla Junior arises from the depths, but takes no notice of his "father" Nick Tatopoulos, or the ship. This causes H.E.A.T. and the captain to track Junior with SONAR, but he soon vanishes below the ship's scan range. The ship's captain allows H.E.A.T. the use of a submarine to check on the scientists, but half way down they are attacked by a Cryptocleidus. Zilla Junior arrives to fend it off, while H.E.A.T. submerged further, and discovered the same ancient extraterrestrial spacecraft that was found by the other scientists in the pre-opening sequence. They begin to explore, but are attacked by Reptilians. They escape by the way of hidden doorways,and find the leader of the scientists Alexander Preloran, but he tells them to leave, on account of this being a "delicate first-contact situation". he later explains to H.E.A.T., that the ship crash landed here in the late Cretaceous period, and that they had been emitting a distress beacon ever since, explaining the tachyon emission. Preloran then traps them in a room, but the team, with aid of N.I.G.E.L., escape. The group follows a tunnel that leads them to a room where Preloran's colleagues are having the information in their minds "downloaded" into a computer. At that point a Tachyon appeared and eventually informed them of their plans for the Earth. They seek to use it as a home for themselves, however the Tachyons require bonding to a human host. The Tachyons then sense defiance among the team, and prepare to punish them all except for Dr. Mendel Craven, who has conflicting emotions about the situation. They offer him a place with them, and he accepts while the rest of H.E.A.T. is tortures in the same fashion as were Dr. Preloran's team. Shortly thereafter, Craven is asked to retrieve information from N.I.G.E.L., where he uses his new-found excuse to to switch in one of Randy's protocols, which results in the robot's going on a destructive rampage in the ship. N.I.G.E.L. eventually crashes into the Tachyon's assumed source of intelligence, because after he does, they all die, and the ship begins to implode. Preloran launches the team out of the ship in a stasis pod, but on their way to the surface, they are cornered by multiple Cryptocleidus. Zilla Junior fends them off, On the surface, it is revealed that the two rescued members of Preloran's party are in fact Tachyons in disguise.