An adorable grandmother lives with her grandchildren on a farm. Every night, she plays with them and tells them a bedtime story. But as night falls, when the children are asleep, the grandmother arms herself to the teeth. Every night, a horde of zombies attacks the farm, and the grandmother mercilessly kills them one by one to protect her grandchildren.

"Malas Hierbas" tells the story of Grandma Hapi, the sweet grandmother by day, zombie slayer by night.