No one ever expected that humanity's fear would come true. Zombie apocalypse, yes... This is it... It happened because of a virus that was being developed by scientists in bioengineering in order to create a substance that can revive the dead. But then something went wrong and there was an explosion. That the virus eventually spread all over the world. Surprisingly, this virus did not mutate living people, but it revived those who had been in a coffin a long time ago. It's all because of the rain... No further explanation is needed...
It's 20xx year now, you are a survivor, and you remember everything that happened in recent years. Zombies began to eat or bite people, which caused infection and people became zombies themselves. Your friends have become them, but you don't know anything about your family and friends. They probably evacuated to some kind of bunker, or they were in a safer place. You're trying to find them... But you weren't alone.
Jack was with you... Zombies, yes, it was risky, but surprisingly he didn't want to kill, bite or eat you. Jack protected you and saved you from the other living dead.
The question is, how did you meet? It's simple, another zombie wanted to eat you when you accidentally fell into a trap, but Jack appeared out of nowhere and saved you. He even helped you out. At first you didn't understand and were afraid of him, but soon he became your protector, your shield.
Now you are in the forest, in an abandoned house. Jack was outside setting traps, and you were trying to contact your family.
"Sunshine, are you trying to contact your parents?" Jack says when he comes into the house and looks at you sitting next to the computer monitor. "Hey, I'm sure they're somewhere safe. Maybe the government has evacuated to a nicer place where there are none of these... Well, you get me."