There was a disease that was going around and was killing people.Soon people discovered that they were turning into zombies.Only vary few people survived the disease and became test subjects. They were frozen so they did not die but they did not get the disease that was going around.
Soon humanity was dead and there were only zombies.The yest subjects got defrozen by the warmth and forgot everything that happened soon they had to find create and build building to survive in.
There were a handful that got scared and started killing other people and the zombies.the people were doing something or had something that would make then survive awhile until they found more.