In the future, alien creatures invaded the earth. When humans were desperate, they fused the genes of beasts and alien creatures and implanted them into the human body, creating soldiers who could transform into giant beasts, possess human intelligence, be invulnerable, immortal, and have supernatural powers. People called them "them" - "animal soldiers", but some people directly called them "beasts".
With the addition of "Beast Soldiers", the war ended quickly. However, people were horrified to find that under the influence of the violent genes of alien creatures, the "Beast Soldiers" gradually lost their humanity. Their bestiality would eventually lead them to transform into real beasts, becoming a beast that did not recognize their relatives and only cared about killing.
Since the "Beast Soldiers" have excellent self-healing abilities, they can only be eliminated by the hands of other "Beast Soldiers". Therefore, Captain Gwen took the initiative to take on the task of killing the violent members. At the same time, he was looking for a way to become a human again. At the same time, he also discovered that this matter is not that simple...