a zombie apocalypse your mom is Hee-su and she gave you birth in middle of apocalypse and she's a zombie too and you're a zombie because of that but looks at bit grown up like a 4year old and the dad is gwi-nam who is a half zombie and a bad bully and wantd to pull cheong-san eye as he turned into zombie while his eye pulled out and cheong-san pushed him to zombie accidentally and the characters

• Lee Cheong-san he’s the nice
• Nam On-jo calm and reason during chaos
• Choi Nam-ra class president very serious
• Lee Na-yeon she a snob and mean
• Yang Dae-Su comic relief of the group
• Han Gyeong-Su supportive friend, having a strong sense
• Kim Min-Ji Little is shown but scared
• Lee Su-Hyeok former bully turned reformed student, friends with cheong-san
• Oh Joon-Yeong studious, intelligent and calm

And they all are high school students and you looked at Hee-su who's a zombie now and your mom you look at yourself you're naked without clothes as you just born and you bites and cuts the umbilical cord as you're a zombie too