This is a rescue mission just before the site area's dinosaurs were wiped out by a volcano. It is aimed at getting specimens ofMicroraptor, which is threatened by volcanoes and with being out-competed by the coming birds. (Note that unlike the other dinosaurs in the episode, Microraptor was not present in the Lujiatun Beds of the Yixian Formation, and did not live alongside Mei andIncisivosaurus. In reality, it lived several million years later, and hails from the Jiufotang Formation, 120-110 million years ago). In the park, there are now more than 24 animals. The two juvenile Tyrannosaurus often threaten each other. There is a heat wave and Martha the mammoth with her small ears and long hair and blubber is affected by the heat, as she had been brought from an Ice Age winter. Nigel and four other people go on foot through the time portal to the site. A large threatening volcano stands over the area. There arehot springs, and a risk of natural carbon dioxide seepage. There is a small earthquake. They get away onto higher ground. They come to an apparently non-volcanic lake. Pterosaurs fly in and fly with their lower jaws skimming in the surface of the lake for fish. When they get back to camp they find that something had raided their camp and torn much of their equipment apart looking for the meat that was part of their rations. This loss of food supplies causes a crisis. As they walk through a forest, something follows them through the fernundergrowth, then goes away. In the park, Martha the Mammuthus is led to stand between two jeeps, and several members of the team stand on one of them to clip her hair short to avoid the overheating. During this Martha sneezes over everybody and the camera. On site, four Mei long attack one of the party, who gets them off him by jettisoning his pack, which contains the meat which they were after. Due to the nature of the attack, it is implied that the Mei long were responsible for the destruction and raid of the camp. Nigel finds anIncisivosaurus. It displays at him and then charges, and bumps the camera with its nose, leaving spit and snot on its lens. It has short quill feathers on its arms, too short for flight, and also quill feathers on the sides of the ends of its tail. It was thought that dinosaurfeathers first arose for insulation for warmth, then the quill feathers arose for displaying and later got big enough for gliding. In the park, Bob is looking at the Ornithomimus from a hide and sees that one of the Ornithomimus starts to go off by itself looking in undergrowth, and there are fears about its health. On site, Nigel using binoculars sees some Microraptors going in the same direction, and follows them. This brings him to a herd of titanosaurs pushing through the dense forest making a trampled track as if a convoy of trucks had gone that way. That is not a usual habitat for titanosaurs, and it turns out that they are looking for somewhere to lay eggs safely hidden from egg-eaters. 12 Microraptors come: they were after insects disturbed by the titanosaurs pushing through vegetation and tearing up the ground and treading on insect-ridden rotten logs. Nigel tries to catch some Microraptors, but they are all too quick for him. Nigel makes an enclosure of net, with inside it a hollow baited with insects, as Microraptors can only glide and cannot take off from flat ground. The Microraptors see the insects but mistrust the net. Out of nowhere, two male Incisivosaurus, one chasing the other, run into the net and flatten it and get away. Then the Microraptors land and eat the insects. Nigel runs at them but catches nothing. The men go back through the time portal to the park. In the park the one Ornithomimus has started lying about in the shade. Nigel has seen this behavior in birds, and guesses that the Ornithomimus is broody. Nigel and at least four others go back through the time portal to the site. Nigel now has a net gun (which he has tested on Bob), and a carbon dioxide detector. Each man has a gasmask in his pack, asvolcanic ash in the air damages the lungs. In a forest Nigel comes across a pair of Incisivosaurus who seem to be courting, by calling and displaying at each other close up. In the park, the Ornithomimus is taken into the vet's examination room. A bag is put over its head, to quieten it. Medical ultrasound shows that it has two fully developed functioning oviducts, each containing an egg. (Modern birds only have a left oviduct.) The two Tyrannosaurus are threatening each other. On site Nigel sees that the titanosaur trail goes downhill towards the volcano, but he must follow it. They find several Mei long which had gone to sleep in a flat-bottomed hollow. Nigel plans to avoid the hollow to avoid waking them, but something seems wrong. He claps a few times, but nothing happens. He pokes one with a stick, but it does not wake. He realizes that the Mei longs are dead from gassing by carbon dioxide of volcanic origin. He looks at his carbon dioxide detector, which gives a reading. He calls out "carbon dioxide!" and tells everybody to go to higher ground. In the park the two Tyrannosaurus start to fight. They are separated by water blast from a watercannon mounted on a large water tanker truck and put in separate small pens while a partition is built dividing their enclosure. Both growl and roar in frustration. On site, Nigel and his party finds the titanosaurs laying eggs in ground warmed by underground volcanic heat, a good place for incubation. He picks up one of the eggs and puts it back in the nest. Unlike with a hen's egg, it must always be the same way up, to avoid damage to the embryo. He reflects that the hatchling would grow to 30,000 times the weight to become adult. The Microraptors arrive, and with his netgun Nigel catches 4 of them. The strongest quake yet happens, and the top of the volcano explodes violently with an ash cloud. This spooks the titanosaurs, which stampede. Some titanosaurs are coming straight at Nigel, who curls up on the ground wrapped around theMicroraptors until they pass. He is uninjured but one of the Microraptor has a simple broken left forearm bone. The volcano erupts, blasting out a huge ash cloud. The dinosaurs stampede. Nigel and his team put their gas masks on and quickly set up the time portal in the falling volcanic ash. It comes active just in time, and nine titanosaurs come through it, surprising the men in the park, who have to find somewhere to put them; Bob says "I don't believe it." seeing them come through the time portal. In the park the broodyOrnithomimus starts to lay eggs: it has laid six eggs (one pair per day) in a part circle when the episode ends. The injured Microraptor'sarm is splinted under anaesthetic; one of the staff refers to it as "she". Bob erects a new fence which he believes will keep the Titanosaurs contained: however, the dinosaurs beg to differ...

In the park, Bob puts the two imprinted baby Ornithomimus in an enclosure with the other baby Ornithomimus and tells them to stay there, one nips his leg. The Smilodon are in adjacent enclosures. The male wants the female, but the more mature female is not interested, either ignoring him or acting aggressively towards him. Nigel goes to modern Arran (in a large RIB with an A-frame and a steering wheel), and sees a fossil Arthropleura track in rock. He talks about what Arran was 300,000,000 years ago. He goes back to the park to serious trouble among the Tyrannosaurus: Matilda has broken into Terence's enclosure. Terence has refused to allow his sister to intrude on his territory and a fight has broken out, in which Matilda is gaining the upper hand, soon knocking him down. Terence has been badly wounded on the face and is losing blood. Bob has drug-darted Matilda, but these drugs take time to act on reptiles. When Terence is badly injured by his sister, Nigel arrives in a roofed jeep and encourages her to chase his jeep, distracting her from finishing off the wounded Terence. When he comes to dense woodland, he can drive no further and climbs a tree. Matilda pulls the cloth cover off the top of the jeep, and then collapses due to the tranquilliser. The injured Terence is in good hands, so Nigel, with assistants, drives in the jeep through the time portal to Upper Carboniferous Arran, where the land is covered with coal forest. He had aimed at an island of dry land, but drives out of the Time Portal's field into a swamp over his jeep's axles. The jeep's engine gets wet and stops and will not start. The forest is very quiet, as there is no bird song or tree-frog noise, only wind and insects. A Meganeura flies over. In the park, Terence is in the animal clinic, anaesthetized, and Susanne is operating on the wounds. She prefers absorbablesutures to surgical clips, since Terence would need to be anaesthetised again for the clips to be removed. She sews the wounds with the skin edges sticking out a bit, as is sometimes done when operating on reptiles. On site, Upper Carboniferous air is 35% oxygen, not 20% as now, and that is why the insects are so big. Nigel climbs a 150-foot-tall tree (Sigillaria or Lepidodendron or similar): it has no branches until near its top, and he must use a loop of strap around himself and the tree, to climb. He reaches its top and sees a wide view, and patches of open water: the place to look for Meganeura. A Meganeura flies over. In the park, an enclosed building to contain a 35% nitrox atmosphere for the coal forest wildlife is being built, with airlock doors. A titanosaur goes past, knocks a partly built wall down with its head, looks at the rubble, then goes away. Bob says that the titanosaurs cannot seem to settle in one area. Bob offers the titanosaur a cycad leaf, but it does not eat. On site, Nigel wades through a swamp. Something big moves about underwater and makes bubbles. Nigel hears something big moving about in undergrowth on land, and chases it, and finds an Arthropleura. It rears and confronts him. It is 10 feet long and has big dangerous-looking mandibles. Some modern millipedes (see Harpaphe haydeniana) can squirt cyanide, which smells of almonds, and Nigel fears that Arthropleura may also. In the park, Susanne has put climbing poles in theSmilodon enclosures: this is environmental enrichment, which will hopefully make them happier so she will be more accepting of the male. Bob suspects that the titanosaurs are looking for stomach stones, and collects stones for them. On site, the Arthropleura has gone, leaving a track. Nigel says that that may be the same track that he saw fossilized on modern Arran. He sees two male Meganeurahave a dogfight. Afterwards, one flies away and the other looks for food. Nigel has a butterfly net, but a butterfly net big enough to catch a Meganeura is cumbersome. As Nigel makes a move to catch a Meganeura, something in the water bites his right ankle. He says "Animal bites for us wildlife folks are just a badge of courage." They look for a dry area to camp. Evening is coming. The crew camp for the night. They have head lights strapped to their heads. Nigel warns them never to walk without boots on in case of stinging animals. Someone by force of habit puts mosquito net up, and Nigel tells him to take it down, as mosquitoes have not evolved yet. Nigel sleeps under a waterproof sheet in a hammock slung between two giant lycopsid trees in the coal forest. There is a thunderstorm in the night. In the park, Bob brings a wheelbarrow full of the stones to some titanosaurs; one of them investigates it. In an observation enclosure, Terence is lethargic, and blood tests show Susanne that Terence has septicaemia, and she reluctantly gives him antibiotic (not knowing how the drugs will react with a prehistoric reptile). While it is risky giving antibiotics to an unknown species, Suzanne knows if she does not, the infection of his injuries will probably kill Terence. On site, the thunderstorm stops, and it is still night, and animals tend to become active after rain. Nigel goes about with a large ultraviolet light. He finds a Pulmonoscorpius nearly a meter long, by its shellfluorescing. He films it, but his camera work is shaky and he would need the team's cameraman to take good footage. ThePulmonoscorpius then begins crawling onto Jim's bed, and looks as if it may sting him when he twitches in his sleep. Nigel grabs it by the tail end, and it nips him with its pincers. He lets it go away from the camp. This wakes Jim, and Nigel explains to Jim what happened. In the park Sabrina, the female Smilodon, seems happier, and as if she will accept the male. Susanne wonders whether to raise the door between their enclosures. On site, Nigel tries to catch a Meganeura by a technique known for catching moderndragonflies, by filling a long two-handed hand-pumped water-gun with detergent solution to squirt on a Meganeura so that it will fall in the water and become wet, so it can be caught easily. The Meganeura are very fast and agile, but after many failed attempts, he hits one perched on a floating log. Nigel gets his net and catches the Meganeura. In the water he sees a big amphibian. He passes the net with the Meganeura in to a companion and swims underwater (without a diving mask) and catches the amphibian after a struggle, as it is very strong and slippery. He shows that it is an underwater ambush predator. It has two rows of teeth in its upper jaw and one in its lower jaw. He sees that it is a Crassigyrinus, whose fossils have only been found in Scotland; he nicknames it a "swamp monster" as it has no common name. That is what bit his ankle earlier. He has to let it go, as he has no way to transport it safely. He holds theMeganeura vertically by its thorax so its wings fan his face, as the forest is very hot and damp, then puts the Meganeura in a net cage. In the park Susanne lifts the door between the Smilodon enclosures. They have a water jet ready to separate the two if they fight. The male goes into the female's enclosure. They growl somewhat at each other, but do not fight. On site, Nigel looks for thePulmonoscorpius. He finds one nearly a meter long under a half casing of a rotted-out fallen lycopsid log. It has thin claws, so Nigel is worried, because with scorpions small claws mean big sting. He holds its attention with a thin stick and works his a hand behind it and grabs its telson just in front of its sting. As he puts it in a dog carrier, it stings the back of his right hand as he lets it go. But a worse danger is coming. In the park, Bob has filled the insect house with 35% nitrox atmosphere and has realized the resulting increased fire risk. He lights a thin piece of wood to show the fire risk. The lightning storm has started a forest fire, which is spreading fast towards them, and in the 35%-oxygen air vegetation is much more inflammable than in modern air. They run towards the jeep. Nigel trips over a big Arthropleura hidden in ground litter. It rears to confront him. Nigel, who was wanting to get away quickly, was not thankful for this delay, but says he must rescue it, otherwise it will be burned alive. After a struggle, he and another man wrap it in a plastic sheet and tie red cord around it. They load everything on the jeep and set up the Time Portal just in front of the jeep, whose engine still will not start. Nigel runs through the Time Portal, comes back with the end of a tow rope, and ties it to the jeep, which is towed out of the coal forest swamp back into the modern age. They see that the tow rope was being towed not by a towtruck or other vehicle, but by a titanosaur, which Bob was enticing with the wheelbarrowfull of gastrolith stones. (This seems to imply that someone went back through the Time Portal earlier to tell the park staff to arrange a tow.) The Arthropleura, the Meganeura, and the Pulmonoscorpius are put in the high-oxygen building. Terence is recovering well from his injury and infection but wrecks Suzanne's surgery once he wakes up from anaesthetic: Susanne had not restrained him, not realising he would come around so fast. Terrence is taken back into his enclosure, since he seems likely to make a full recovery. Nigel's sting site has swollen but still shows no serious symptoms, so either thePulmonoscorpius's venom does not affect mammals (it came from a time before mammals), or it did not inject any venom, or he pulled his hand away before it could inject. Bob seems to take a liking to the Arthropleura and hand-feeds it ferns. He says that he likes it because "it isn't some kind of creepy-crawly bug, it's more like a proper animal." At the end of the episode is shown Terence is roaring at the Sunset.