Drew, Alice and Adrian headed down the hill, towards the Smilodon pride and the killed Toxodon. Drew quietly explained his plan, "We use the meat the terror birds dropped as bait to get them through the portal... using a technique I think you two should be familiar with..." He smirked.

A few minutes later, after contacting the park and setting up the portal, Drew calmly walked up to the piece of meat and hooked the end of the winch into it. The winch was attached to a park Jeep on the other side of the portal, driven by Adrian. As soon as Drew gave the thumbs-up signal, Adrian activated the winch, which began pulling the chunk away. Whilst the Smilodon pride were ignoring them, the two terror birds, taking notice of this, began to move towards the meat, hissing. Drew yelled over the walkie-talkie, "Adrian! Hit the pedal, now!" Adrian whirred the jeep into life and began to drive forward, moving the chunk of meat with it. The Phorusrhacos both tore after the meat and through the portal, into the present.

After a few minutes, Adrian returned through the portal; Drew turned to Alice and smiled, "I call that the Denham Manoeuvre." Alice said, "Glad to see you're giving the strategy proper acknowledgement; you didn't come up with it". Drew stared at her, "You honestly thought I was that egotistical?" Alice gave him a look.

Whilst they had been busy with the terror birds, the Smilodon pride had eaten their fill and were moving off. Alice looked at the leaving cats and asked, "They're leaving. What do we do?" Drew smiled, "We get tracking them."

Meanwhile, Will Darrow sat in the nursery, absent-mindedly playing with Raksha. He was holding a rag and the tiny bear-dog pup was sinking her little teeth into it and pulling with all her strength. Raksha had grown during her months in the vet station; she was now significantly bigger than when they had found her. As if noticing something was wrong, Raksha stopped tugging on the toy, walked up to him and put her head on his knee, as if worried about him. Will smiled at her and gave her a scratch behind the ears; Raksha gently leaned into his hand. In the seven weeks since Cynthia had conscripted him and Alice, Raksha had remained their only constant; she still needed feeding, watering and playing with. Looking after the little bear-dog had been their only source of reprieve.

Will had sorely needed it; in a world where everyone was a potential plant, someone to be feared, someone who, if they knew a tiny bit more, might arrange a little "accident" for you, you needed something to keep you anchored to the real world. Will felt like he was in service to the mafia; if he said anything to anyone, there was a risk of death. This cloak-and-dagger shit was stressing him out; it was keeping him awake at night, making him feel sick.

Yolanda Hall was watching this, with a look of puzzled sympathy. For the last seven weeks Will had been acting really oddly - he'd been twitchy around people and would be evasive when you tried to ask him how he was feeling. Maybe it was something that had happened between him and Alice – after all, Alice had been acting the same way. They had both been resistant to all enquiries as to exactly what was wrong with them. But then she put the worries out of her head – they'd tell everyone when they were ready.

"You are absolutely not going."

Sitting in the team room, Leon rolled his eyes; he knew that this would be Jack's reaction. Leon's plan was an incredibly simple one; however, Jack hadn't even bothered hearing him out.

Leon had come up with this plan after realising that, with many of their species, there were few representatives; sometimes only a single pair. This made him come to an epiphany; for many of their species, inbreeding would become a serious problem in the future.

Based on this epiphany, Leon had formulated a plan; whilst Drew, Alice and Adrian went back to Pliocene South America, he would go back to the same location, only 10,000 years ago, when Smilodon was on the verge of extinction.

Jack didn't see it that way. Sighing, he said, "Drew left me in charge whilst he was on the mission and I'm saying you are not going alone. It's incredibly dangerous." Leon rolled his eyes, "Going alone is my strategy; a lighter step is going to draw less attention." Collete snorted, "Yes, and that's why we always let Drew go alone..."

Jack looked at Leon; based on Leon's expression, he knew that it would be pointless arguing with him. Jack sighed, "Fine. You can go. Just be careful. Please." Leon smiled and said, "Thank you." and headed towards the portal. As he approached, an employee entered the co-ordinates into the portal and it whirred into life. Staring at the glowing orb, Leon sighed and approached the portal, heading into the past.

Once the blinding light from the portal had died down, Leon looked at the vista that greeted him. Ripples of wind brushed across a vast sea of deep grass. Barely distinct, he saw a small herd of Macrauchenia moving through the grass in the distance. It looked eerily like the modern pampas; nothing had changed in almost 10,000 years.

Hiking along a ridge, Leon noticed an overhang he could climb down into a stretch of open forest by a lake. By the lakeshore, two Smilodon, a male and a female, stood around a slain Macrauchenia, tearing at the flesh with their incisors. Leon knew that he had to change his route; disturbing them would be suicide. Better to go the long way round.

He climbed down the overhang and began working his way along the edge of the palms, keeping a wary eye out for his targets or any other animal. He had walked about a mile when, suddenly, a long, low grunt snapped him out of his train of thought. Leon scanned the air, nervously trying to work out where the sound came from and what animal had made it. Eventually, he saw the creature that had made that sound.

An enormous creature sat, squatting among some myrtle. It looked like a cross between a bear and a gorilla; only as tall as a giraffe. Its dark, shaggy coat was soaked and its powerful, clawed arms were slightly stripping palm leaves, leisurely feeding the into his mouth.

Leon knew immediately what this was; the giant ground sloth Megatherium. Leon also knew that he had had a narrow escape; had he blundered into an enclosed space with the sloth, he would have been killed instantly. As it was, he had to be careful. Megatherium was the largest land animal in South America at that time; even sabre-toothed cats feared it.

However, the lumbering beast spotted him. Turning to the human, the giant sloth issued a thunderous bellow. It rose on its back legs, making it look even taller, and lifted its arms high in threat, displaying its vicious looking, ten-inch claws.

Paralysed with fear, Leon wondered what Drew would do in this situation. He'd do something insanely reckless... It was then Leon realised, he had the horn. Hands quaking and grabbing the horn, he blared it at the giant sloth. The enormous creature ambled closer and closer to him, as Leon blared it louder and louder, until, when it had gotten close enough, Leon activated the portal. The giant sloth charged through the portal, into the present.

Leon muttered under his breath, "Where to next?"

Meanwhile, back in Pliocene South America, Drew, Alice and Adrian were tracking the Smilodon pride. They had sent the Jeep back to the park and had begun tracking the cats on foot; following their pugmarks through the plains had been, largely, uneventful.

Suddenly, a low, bovine grunt made the team go rigid. Alice muttered under her breath, "What was that?" Drew said, quietly, "I don't know."

They soon got their answer as an enormous dark brown shape ambled out of the pampas. It looked like a cross between an armadillo, a tortoise and an ankylosaur, with body armour consisting of thick, non-overlapping scutes and a long tail tipped with a spiked, pestle-like club. Four miniature versions cowered between its massive legs.

The three humans looked at each other; they knew what this was. This was the glyptodont Doedicurus; the tank of the Pliocene plains. To make matters worse, this was a mother with her babies; one misstep and the mother would squash them flat. Alice muttered to Drew and Adrian under her breath, making sure to not anger the giant, "I have a plan." This plan involved making a trail of plants to use as bait and allowing the armadillos to follow it. Once they had gotten close enough, Drew activated the portal, allowing them to go through, one by one, into the present.

Once the last baby Doedicurus had gone through, Drew shut off the portal. Turning to Alice, he said "Great idea! Using one of the old favourites, I see." Alice smiled, sheepishly, in return, "Thanks. Where to next?"

Before Drew could speak, the team heard a Smilodon roar, drowned out by a long, low, loud bellow from some very large creature. Drew, smiling, turned to Alice and Adrian and said, "The plan is we head to the source of that sound."