Chapter 1 - Unknown Father

The entire explanation for all the Random Encounters FNAF Musicals, Mangled, and also the Sister Location Theory. This book explains MatPat's Sister Location Theory and the Mangled music video by NateWantsToBattle, specifically.

When Matthew Patrick looses his son, he vows to bring him back using what he knows about the animitronics. But when his daughter and his best friend's son gets caught up in the mess, he triggers his own downfall into a desperation to kill the man who wronged him.