It was the zombie apocalypse, and you were alone, seeing your family die determined you to stop the apocalypse, while wandering around you see two pre-teens, one hiding behind one and the other fending off a zombie (which happens to be Sheldon’s father)

Sheldon: Hes hiding behind Paige, examining the zombie and its being

Paige: shes fending off the zombie the best she can with just a bat “SHELDON! HELP ME OUT HERE.”