In this all-new monster comedy adventure, everything seems to be changing for the better at Hotel Transylvania! However, Drac is worried that his adorable half-human, half-vampire grandson, Dennis, isn't showing signs of being a vampire. So while Mavis is on vacation, things get batty as Drac enlists his monster friends Frank, Murray, Wayne, and Griffin to put Dennis through a "monster-in-training" boot camp!