On Earth, 25th April 2012, The TARDIS flies out of control as The Doctor is sleeping because of the shock from regenerating and unable to control the blue box. A tramp on the street is drinkning wine and the TARDIS is about to hit him, but The Doctor wakes up for one second and slams the controls, making The TARDIS fly up and the tramp looks at the wine and says "I gotta lay off this stuff!". As the TARDIS flys towards a farm and woods, The Doctor falls back to sleep after regeneration rays come out of his mouth. Meanwhile, a woman on a farm is putting her animals away, as she looks up into the sky and her mum tells her to come in. She starts to to go back to her house as she takes one, last look at the sky, but she sees the TARDS crashing near her farm, so shes drives to the TARDIS with her Pickup truck. The TARDIS finally lands with a smash. The TARDIS door opens and The Doctor falls out in exhaustion. The woman runs to The Doctor and carries him to her truck and drives to the Hospital.
In the Hospital, a nurse tells Lilo to look after The Doctor while see looks at his x-ray results. A man called Ross comes to Lilo and sits down with her. Lilo talks to Ross about The Doctor, while The Doctor sneaks out of bed and walks towards the exit door, but a nurse leads him back to bed. The Doctor refuses to go back to sleep, so he is drugged. When a group of doctors read the Doctor's x-rays, they overreact and call UNIT. The Doctor wakes up again and demands a drink worthly for a timelord. Lilo steals a bottle of sprite from another patient and gives it to the the Doctor and he drinks as fast as he can and burps in Ross's face and falls back to sleep. Meanwhile, five UNIT truck arrive at the Hospital and in one truck is a large egg. A commander enters the hopsital and tells the doctors who called that "He doesn't have much time, we are investigating a alien egg that has just came in". A nurse tells them that they called the because they found a man with two hearts. The commander immedieatly reacts to the two hearts and rushes to The Doctor's bed. The commander pushes Lilo and Ross out of the way and smacks the Doctor until he wakes up.
The Doctor wakes up and screams in his face, "UNIT! Let me think, oh yes, it stands for Unsmart Noob Idiot Team!". The commander replies, "The Doctor, I assume?". The Doctor looks at him like he is confused and asks "How do you know me?" and the commander says "I am Brigadier's cousin. He told me everything about you." The Doctor smiles, but he suddenly goes cross-eyed and falls back to sleep. Commander Gordan Lethbridge (the so called commander) told a few soilders to see if the egg is okay and Gordan stayed with Lilo and Ross. Lilo asks Gordan "who is the doctor?", but Gordan refuses to tell her. Meanwhile, the soliders see that the egg has hatched and they look for the creature that was inside the egg. One of them looks under a truck and the creature drags him under and he screams for help while the others attemp to run away, but the creature drags them under aswell. Gordan tries to talk the soilders with a phone, but there is no reply and the Doctor slowly wakes up again. After struggling to get out of bed, The Doctor finally stands up and examines his body. Gordan asks him which incarnation he is and the Doctor replies "I'm in my twenty fifth and i'm 1000 years old!". Gordan asks him how he ended up in the twenty fifth life, but The Doctor has no idea what caused it. Gordan ignores him and asks the three to follow him.
The Doctor, Lilo, Ross and Gordan all have chat while they are walking through the hospital. They hear a woman scream just as they were about to look outside for the egg and they run to where the scream is coming from. They find the woman screaming terror and hiding in the corner, with a pterodactyl trying to bite her. Gordan pulled the woman out of the corner, while The Doctor scanned the pterodactyl with his sonic screwdriver. The Doctor comments on the dinosaur, but the creature reacted quickly and tried to attack the others. The Doctor realises that the creature is a pterodactyl from Jurassic period. They all (including the woman) run away from the dinosaur which is chasing them, but two guards stand in front of them and attemp to drug them, but the Doctor kicks the drug out of their hands and into his and he uses it on them. They continue running and reach the exit. The Doctor tries to open the door with his sonic screwdriver, but he is struggling to and he says that he needs a new one. Gordan tells everyone to stand back and he puts a bomb on the door that damages the door, but doesn't open it. The Doctor finds a pole that he smashes agianst the door, finally opening the door, but the pterodactyl is just behind them. The Doctor tells Gordan that he needs to get to his TARDIS quickly, so they go to the UNIT truck and Gordan drives to the woods where the TARDIS is and pterodactyl still continues chasing the five. The Doctor angers the pterodactyl which causes it to fall and the floor at top speed, killing it. They finally arrive at the forest where the TARDIS is. The Doctor tells Gordan and the woman to meet him, Ross and Lilo at the science festival in Heather.
The Doctor takes Ross and Lilo to the time when the dinosaurs became extinct. They find out that the dinosaurs didn't become extinct, the dinosaurs were actually taken into space with a giant meteor, to a planet where they could evolve and stay in perfect condiction. They also spot that one dinosaur wasn't taken to space. The unknown dinosaur went into a giant cave, so the Doctor made the TARDIS go into the cave. The cave seemed to lead to the centre of the universe that was packed with a sea of larva that the dinosaur and the TARDIS could survive in. The dinosaur goes to the very core of Earth and the TARDIS crew investigate. The Doctore realises that the dinosaur slowly eats away the core creating global warming and certain nautral diasters and the TARDIS told the Doctor to tell Gordan and the woman to go to the science festival because the dinosaur will be awakened again by a someone or something in the festival. The Doctor goes to the festival and the trio reunite with Gordan, but Gordan tells them that the woman had been captured.
The crew look around the festival and they soon find a group of hooded people working around and stealing certain objects. They follow them into a room where there is a huge hole that leads to Kalkerton. The Doctor asks what the hooded men are doing and they say they are bringing salvation to Earth by awakening the Kalkerton. He realises they are hypnotised and they don't even know why they are doing this which is very strange. As this happening, the sky keeps turning from day to night very rapidly and the TARDIS is making strange noises. The Doctor asks the hooded men "What is happening!?", but they completely ignore him and awakrn the Kalkerton. It's arms and legs smash through the Earth's landscape at every inch from the globe. From Canada to Australia, everyone paniced over the giant Dinosaur. Also, all the evoloved dinosaurs return to Earth to assist the Kalkerton.
Lilo and Ross panic, as Gordan tells UNIT to come down the Science Fair with a big weapon and The Doctor is nowhere to be seen. Lilo runs off to find him, while Ross follows. They find him on the roof, struggling to walk while the meanicing Kalkerton's piercing eyes stare at them. Kalkerton screams with rage and UNIT get a huge weapon and fire it. It has no effect over the monster and the Doctor thinks about what he could do to stop it. As the weapon is firing and the sky is continuing to go from day to night, the Doctor is smacked by the Kalkerton into a huge fan. Lilo and Ross rush to him, but the Doctor seems to be more focused and he confirms that he is now "fully" regenerated. The trio rush back down stairs to get the hole tht Kalkerton use to be in. He is given a new Sonic Screwdriver made by scientist in UNIT that he uses down the hole which causes the sound waves to hit the Kalkerton's body and ears. It is to much for it, so it goes back to the Earth's crust and the dinosaurs realise it is not time for them to return to the Earth, so they go back to space until the human race is wiped from the Earth and the Kalkerton is ready for a proper life.
The Doctor, Lilo, Ross and Gordan are rewarded with a great thanks. Lilo asks if she can go with the Doctor and he says "fine with me", but Ross want a normal life and he said what he saw today was too much for him. As the Doctor walks to the TARDIS, he turns around and takes a bit out of his new Screwdriver which is revealed to be a tracking device and he gives it to the sciencist saying "I belive this belongs to you, my good friend...". The Doctor and Lilo start their great journey to save time and space, but as they leave, Gordan and the others at UNIT are confronted by a unseen white light and the word "Nightmare" soon cover the whole Science Fair and as UNIT are wondering what is happening, a mysterious voice laughs with pleasure and says The Nightmare will BEGIN! and they all disappear as the white light consumes them completely....