RandomBVBFangirl
Note-I know the first chapter doesn't have Andy, but just read it to understand what's going on
One day, Heather realizes that her mother hasn't returned from taking her cat to the vet. After a while, she realizes that there isn't anyone going past her house, and nobody is responding to her texts. Eventually, she finds Andy and together they try to find out what happened to the other 7 billion people on the Earth