dead and buried

We never expected the world to be overruled with zombies. It has been nothing but a dead zone straight from a manga. Katsumi, Who is 17 years old, wishes to find the rest of his friends with Naozumi and Kaida. One day, they find Shohta and a lost friend Junpei. But because of this moment, The friends knew that the Zombies still remember their past. Because of this, Katsumi and the rest try their best to remember each of their childhood past, if at least one of their friends are zombies. What would happen?

I'm very new to this