While scouring the sewers of New York, Nick Tatopoulos discovers one of Godzilla's eggs has survived. The hatchling that emerges escapes and by the time the team find it again, has grown to a massive (but thankfully harmless) sub-adult. As the team try to study the new Godzilla, the U.S. military, responding to a series of disappearances in Jamaica, attack!
After believing that the new Godzilla has been destroyed by the military, Nick convinces his newly established H.E.A.T. organization to stay together in order to investigate the other mutated creatures that he expects to appear across the globe – and they agree, beginning their investigations with mysterious ship disappearances in Jamaica.
H.E.A.T. travels to Central America to investigate their latest creature sighting and they encounter a dangerous, subterranean monster that resembles something of an enormous hybrid of an earthworm and a slug.
Nick is contacted by Cameron Winter, an old college buddy, with an offer of hiring H.E.A.T. Allegedly towards this end, Winter entices Randy to plant an experimental computer-operated device upon Godzilla that, unknown to Randy and the rest of H.E.A.T., is actually for the purpose of controlling Godzilla.
A new form of microorganism is created, designed via genetic engineering to consume oil spills and other manmade pollutants in New York City but it mutates and becomes an enormous, ever-growing mass of protoplasm that devours everything in its path.
A colony of huge mutant rats appear on the scene, wreaking havoc on the sprawling metropolis at night. Soon, the problem is escalated as Godzilla appears and begins to attack the rats in defense of his territory, thus causing more destruction to the city.
A powerful gigantic monster possessing the ability to discharge crackling bolts of destructive electrical energy suddenly appears in the middle of New York City and begins wreaking havoc, only to mysteriously disappear in the midst of an attack.
Nick and H.E.A.T. go deep beneath the sea in order to investigate the mysterious disappearance of noted scientist Dr. Alexander Preloran and his own research team, and there H.E.A.T. discovers a hidden spacecraft belonging to a race of advanced, hostile non-humanoid aliens that hope to conquer the Earth with the help of a pet giant monster.
H.E.A.T. investigates the tropical island of Santa Marta in the wake of a devastating volcanic eruption. But what they find on the island is that, due to irradiated lava, a hideously mutated ecosystem has developed, including carnivorous plants and gigantic bees. As the volcano begins to erupt again, the team must find a way to escape the island alive.
Mexico is under siege from a mutated beast that resembles a gigantic winged lizard, which is named Quetzalcoatl after the mythological Aztec deity whom it also resembles. H.E.A.T. investigates, and discovers that the flying beast is guarding a nest whose eggs are soon about to hatch, thus creating the threat of numerous such creatures terrorizing the planet.
H.E.A.T. journeys to Loch Ness in Scotland, in order to search for (what else?) Nessie, the famed Loch Ness Monster herself. This is because the famed Loch Ness Monster has eschewed her usual shy mein in order to inexplicably attack a Scottish scientific institute.
As tension threatens to break the H.E.A.T. team up for good, major problems arise: a giant bat is terrorizing the countryside of Nigeria, the U.S. military have dredged the Leviathan ship from the bottom of the Pacific, and worst of all, the aliens are back, with an army of monsters under their control and plans to conquer the Earth.
From their secret base on Isle Del Diablo, the aliens assemble their forces. H.E.A.T. desperately fights to resist, but are easily defeated. Once captured and brought to the Tachyons, they are told that the monster army, including a brainwashed Godzilla, will be used to attack major cities across the world in preparation for a full-scale invasion of Earth. At its head marches the aliens' ultimate weapon: Cyber-Godzilla.
As the aliens and their monster allies attack Earth, H.E.A.T. escapes captivity. They battle to defeat the alien onslaught and free the monsters from their control to help humanity fight back and save the planet from conquest.
A trip to Japan to investigate a number of mysterious disappearances leads to a battle of wills between H.E.A.T. and the Japanese military, who perceive Godzilla to be a threat. However, the real threat is revealed to be an ophidiaphobic's nightmare: a mutant King Cobra. Things lead to a climactic showdown in Tokyo between him and Godzilla.
H.E.A.T. are dispatched to aid the investigation into the disappearance of a search party looking for oil in Antarctica. The team must now not only battle against the monsters responsible — a pack of mutant "Ice Borers" — but also against the energy company who employed the men, who are determined to brush all record of the incident under the rug.
Godzilla is throwing infantile tantrums and H.E.A.T. are growing worried about their ability to control him. When Audrey lets this slip on live TV, despite being told in confidence by Nick, their relationship looks set to be torn apart. Meanwhile, when called in to investigate extensive deforestation in the Amazon Rain forest, they discover that a mutated termite colony is devouring the forest at an alarming rate. H.E.A.T. must find a way to destroy the voracious bugs before they devour the entire rainforest.
H.E.A.T. is charged by the Pentagon to investigate the growing population of spiders near an Army base in the Canary Islands. The team quickly discover that a massive mutated female black widow spider has been laying millions of eggs. They must find a way to destroy the infant spiders and help Godzilla take care of the mother.
When Godzilla is accused of attacking New York, the military call in H.E.A.T. to help contain him. But Phillipe Roache has returned from France... with orders to terminate Godzilla. However, H.E.A.T. discover the real culprit is a hideous mutation called the Chameleon, genetically engineered by Cameron Winter (who has escaped from jail) to frame Godzilla. Can they stop Winter and reveal the truth before it's too late?
The Techno-Sentient, an alien piece of technology, falls to Earth and begins to bond with all manner of human technology, growing to gargantuan proportions. Worst of all, it taps into the Internet and learns of the location of humanity's weapons of mass destruction. The team and Godzilla must find a way to stop the Techno-Sentient before it takes control of an arsenal of nuclear missiles.
Acting on confidential information from Phillipe, H.E.A.T. investigate an abandoned lab in the Amazon jungle, where 50 years before, French scientists succeeded in creating a creature made of pure DNA. The creature is capable of mimicking the shape of any living creature it touches, and soon the team are put on edge, uncertain who to trust. They must find a way to aid Godzilla and destroy the creature before it can reproduce and go on to create a new master race of monsters.
While pursuing a mutated jellyfish, a mysterious storm propels the H.E.A.T. team into the year 2022. There, they discover a post-apocalyptic future where Godzilla and the other monsters are all dead, humanity is all but extinct, and the world is overrun by terrifying creatures known as Dragmas. As the team battle for survival alongside future versions of Craven and Hicks, they discover that the Dragmas were created by the scientist Johnathan Insley. After narrowly making their way back to the past, they decide to stop him before he can create the monster race. But Insley's Democratic Resurgence Against Global Mechanized Armageddon (D.R.A.G.M.A.) project is ready to be activated, and now the team must battle to destroy Insley's work before the Dragmas are unleashed and the bleak future they saw becomes reality.
In the middle of an attack on H.E.A.T. headquarters by a giant water beetle, the team is shocked to find Godzilla is not responding to their distress call. After fending off the beetle, the team discovers that the billionaire Maximillian Speil is hosting a monster fighting ring: with Godzilla as his new main attraction. Now with Audrey and Animal in tow, the team must save Godzilla from a brutal fight to the death against other mutations.
Told in a documentary style, the H.E.A.T team are called to Miami to deal with Skeetera, a giant mutated female mosquito, when they come under attack from S.C.A.L.E. (Servants of Creatures Arriving Late to Earth), an eco-terrorist group - led by Alexandra Springer who believe mutations are the next stage of evolution. After narrowly capturing the rampaging insect, H.E.A.T transports the Skeetera to Monster Island so she can be studied by the U.S. military. But unknown to them, they have unwanted guests: Animal and Audrey have stowed away on board the 'Heat-Seeker', hoping for a good story, and S.C.A.L.E. has tracked them to Monster Island. When the terrorists take over Monster Island with plans to release the monsters held there, the only hope lies in the combined forces of H.E.A.T, Major Hicks and his troops, Audrey and Animal.
Archaeologists in Egypt accidentally reawaken Norrzug the Iron Lion, a gargantuan sphinx-like monster that once served as the guardian of the ancient city of Amon-Ra. H.E.A.T. discover from ancient texts that the people of the city deliberately rusted the creature to stop its rampage after it turned on them. Now the team must find a way to repeat the feat before this mythological terror devours every last drop of oil in the Middle East.
When circus ringmaster Tobias Wilson brings his "Weird World of Wonders" mutation circus to Manhattan, things go terribly wrong when a mutant sea anemone called Medusa escapes her tank and goes on the rampage. When the team discover the creature is sucking water out of her victims, as she needs the electrolytes found in water to survive, the race is on to stop Medusa before she drains every drop of water on the planet.
While on a romantic cruise to Alaska, Nick and Audrey's ship is attacked by a mutant turtle, but they are saved - not by Godzilla, but by Komodithrax, a mutant Komodo dragon. When Godzilla heads for Alaska to find Nick and H.E.A.T. follows, they make a shocking discovery: Godzilla and Komodithrax are in love and Godzilla has become the surrogate father to an egg laid by Komodithrax. The menacing turtle is still nearby, however, and the U.S. military is ordered to destroy all monsters in the area, leading to Nick and the team to try to protect the two gargantuan reptilian lovers.
While fighting a giant mutant germ named Bacillus, Godzilla is infected by the bacteria and left fighting for his life. While Elsie, Randy and Mendel create an antibiotic to weaken the bacteria, Nick and Monique must enter Godzilla's body and destroy the infection at its source before Godzilla dies.
When Elsie's estranged parents come to New York for her spoiled sister's wedding, she is forced to attend as maid of honour instead of helping H.E.A.T capture a mutant manta ray. When the military's battle with the creature ends up interrupting the wedding, Elsie is determined not only to catch the creature, but also to prove to her parents that she is not the screw-up that they think she is.
Shortly after receiving an anonymous check for $5 million, H.E.A.T. are called to Illinois, where a gigantic mutant chilopod, the Megapede, is devouring thousands of dollars worth of crops. The team are unable to stop the creature when they first encounter it and upon finding it again, they discover it has metamorphosed into a Giant Cicada. The insect's mating call is disrupting all radar in Chicago and now H.E.A.T must find a way to silence the creature long enough to launch a counterattack.
Just as H.E.A.T has had it with Randy, Elsie convinces the rest of the team to investigate a possible mutation sighting at Area 51, where they discover the real secret of Area 51 is not aliens but mutations, created by underground nuclear testing. When one of the captive mutations - a mutant thorny devil (a species of lizard) - breaks out of its cage, the team and Godzilla must stop the creature from escaping the base and destroying nearby Las Vegas.
During a nice relaxing day at the beach, the team is caught off-guard by a twister. They trace its origins to an experimental energy experiment at a local power plant, as well as discovering strange tracks near the plant. When the twister strikes again, H.E.A.T. discover that a giant mutant shrew has been bonded to the twister, creating a "Shrewster", and now the race is on to defeat it before its ravenous metabolism drives it to eat everything in New York.
On their way to an expo in an attempt to win a research patent, the team meets a lost young girl named Meg. She asks the team to rescue her two brothers Steven and Kevin, who went into a silver mine where a gang of miners disappeared without a trace fifty years before. While Monique is left babysitting Meg (much to her displeasure), the rest of the team encounters the Silver Hydra: a monster capable of encasing anyone unfortunate enough to meet it in silver and able to regenerate itself every time it is harmed. Now the race is on to defeat the Hydra before Kevin, Steven, Elsie and Godzilla end up as lifeless silver statues.
While tracking Godzilla to Fort Armstrong, New Mexico the team discover a gigantic mutated scorpion, called Ts-eh-go by the locals, is on the rampage. But when they try to contain the monster, they come under fire from U.S. military under the command of Colonel William Tarrington, an old friend of Hicks, who is out to destroy both Ts-eh-go and Godzilla. When H.E.A.T discover Ts-eh-go was created by the army's 'First Wave' program, and that Tarrington is planning to use the creature's offspring -codenamed 'Second Wave'- as bioweapons, H.E.A.T and Hicks must convince Tarrington to stop when the scorpions get out of control.
Cameron Winter springs Dale, Bill and Hank, the redneck hunters from "Cat And Mouse", from jail and uses them to pilot the "Lizard Slayers": three extremely well-armed battle mechas (a giant robot, a tank and a jet plane) programmed with one mission: to destroy Godzilla. When Cameron takes control of H.E.A.T.'s computer systems to stop them from intervening, Nick and the others must get rid of Cameron, then find a way to save Godzilla from the three hunters.
Another new and dangerous mutant species appears on the scene, this time in the form of gigantic hummingbirds that attack planes flying over San Francisco. Worst of all, this mutant avian species is able to render themselves invisible via the hummingbird trait of flapping their wings faster than any other bird species in the world. As a result of their ability to cloak themselves so as to be invisible to the unaided eye, Godzilla is unable to see the creatures in order to attack them.
The team is split up due to a lawsuit by the city of Miami (over damages caused by a giant mutant vampire bat). While Nick, Monique, and Elsie deal with the lawsuit, Randy and Craven decide to deal with a mutation (without Nick's permission) in Michigan. The mutation in question is Armillaria, a giant fungus with the ability to suck the amino acids out of any living thing. It swiftly proves too much for the duo, who end up trapped in the wilderness with nothing but their wits and the clothes on their backs. Once the others hear of their antics, the race is on to rescue the duo and defeat Armillaria before it sucks Godzilla dry.
The Fire Fly, a strange creature made of living flame, attacks an oil platform in New Mexico. When H.E.A.T. and Godzilla arrive to stop it, Randy and Craven sense a chance to make a lot of money if they can exploit the monster's ability to regenerate energy. Once H.E.A.T has taken the creature out, Randy and Mendel sneak it back to headquarters for study, but things go terribly wrong when the Fire Fly regains consciousness and starts burning down everything in its path.
While in New Orleans covering Mardi Gras, Audrey hears rumors of a strange "Swamp Beast" and decides to call in H.E.A.T.. The creature swiftly proves itself a match for Godzilla and the team begin to suspect something is afoot when the locals claim the beast is the swamp's revenge against corrupt local politician, Paul Dimanche, who wants to mine oil in the bayou. But can they prove it before the Swamp Beast destroys New Orleans?
When the 'Deep-Dweller', a huge mutated frog fish begins to attack boats and fishing ships off the coast of New Jersey, H.E.A.T. must help Godzilla drive the creature back to deeper waters, while dealing with the interference of the sleazy and obnoxious tour promoter, Milo Sanders, who hopes to make money by getting good footage of Godzilla.
