Fan Casting Cold War : Mythological Case

1975, the Vietnam War has just come to an end and American troops have left the country, with the shame of defeat. However, during a final mission there, the best Colonel Morgan's men, a soldier who had difficulty digesting defeat, managed to find a top secret file that the Viet Cong shared with Soviet allies. They discover the existence of an island hidden in the mist, not so far from Vietnam, not found on any map, where there is a weapon that would allow Mother Russia to win the Cold War ! While the Kremlin has already sent men there, Uncle Sam is doing the same with an entire army that would like to return to the USA, but they're promised that this will be their last mission. However, on this vast forest island, there are creatures who only wanted to live peacefully, but who once again are bothered by humans hungry for a power that they cannot control anyway ! Still having bad memories because of what they lost thirty years earlier, the children of Echidna will not differentiate between the Soviets and the Americans, who, if they want to survive, will have to consider a very difficult option : collaborate ! However, in this remote place, the worst monsters are not necessarily those you think of at the first place...