|“||This is life's forgotten story. An epic war for our world. A war between monsters.||”|
During an unknown time period, the Earth is shown from space. It is a toxic planet, with no hope of life. However, another planet Theia, crashes into the Earth, forming a moon and making the new planet habitable. Soon, oceans form, and life evolves.
In the Cambrian, the land is still dull, with barren deserts and no life. However, in the seas, life is beginning to take hold. Vast hordes of jellyfish and other soft-bodied animals dominate the ocean.
In the shallow coastal waters, a Trilobite is ambushed by an Anomalocaris - the worlds first super-predator - and is torn apart and eaten. Anomalocaris is one of the first animals to have evolved eyes, and the prey items are evolving them too. This has created an evolutionary arms-race.
The Anomalocaris passes two others of its kind. These two begin to fight, grabbing each other from above with their tendrils. Eventually, one manages to bend and snap the others armour.
The loser Anomalocaris swims away, but its injury has made it vulnerable - a shoal of tiny Haikouichthys attack it. Haikouichthys are the very first backboned animals, making them faster and more agile than the invertebrates, and enabling them to scavenge flesh and dart away unharmed.
However, Haikouichthys must adapt, and they evolve into Cephalaspis.
Elsewhere, multiple sea scorpions crawl around a reef, along with Giant Orthocones, Pterygotus, and Cephalaspis shoals. In these reefs, some life is starting to look recognisable - sea sponges and urchins stick to various places.
An entire shoal of Cephalaspis is chased from some rocks by a metre-long sea scorpion, who quickly finds a lone Cephalaspis to attack. However, special sensors on the Cephalaspis' head allow her to detect the scorpion approaching, and she flees, pursued by the scorpion.
Because of her heavily-built head, the Cephalaspis must stop to rest frequently, allowing the scorpion to catch up to her. However, she detects more vibrations - something the scorpion cannot do. As she turns away, a Pterygotus - an even larger type of sea scorpion - bursts out from below the sand and kills the Brontoscorpio. The dead scorpion makes a meal for her and her babies.
A large shoal of Cephalaspis soon migrates to freshwater spawning pools within the continent- which is now covered in Cooksonia plants. To do this, they are forced to leap over small bridges of land. However, the sea scorpions follow them - the scorpions are the first true land animals.
After the Cephalaspis lay their eggs in the spawning pool, they attempt to leave across the small bridge of land - before they can do so, they are found by the scorpions. The scorpions kill many of the fish, but the Cephalaspis have numbers on their side, and many survive. One scorpion is forced to shed its skin to grow, and misses the feast.
Soon, Cephalaspis evolves defenses, and becomes Hynerpeton.
In the Devonian, life on land has finally begun. Vast forests dominate the landscape, with nothing around to eat them. Hynerpeton is the first vertebrate to come onto land, but is still an amphibian - it must stay around the water.
In the water, a Hynerpeton is pursued by Stethacanthus, a primitive type of shark. However, the shark is promptly eaten by an even bigger predator - the giant fish Hyneria. The Hynerpeton manages to clamber onto land and escape the fish.
As dusk falls, the low heat enables the Hynerpeton group to stay on the land for longer, where the males compete for mating rights. At night, a newcomer arrives and challenges a struggling Hynerpeton, but is defeated in a sparring match.
The victor manages to attract a female Hynerpeton the following morning. The pair mate half in the water, and eggs are laying during the mating. This attracts the attention of a Hyneria, which hauls itself onto the land and drags the male away.
The Hynerpeton eggs, of which vast swathes survived, eventually evolve shells - the very first reptiles have evolved.