Everything seems to be changing for the better at Hotel Transylvania… Dracula's rigid monster-only hotel policy has finally relaxed, opening up its doors to human guests. But behind closed coffins, Drac is worried that his adorable half-human, half-vampire grandson, Dennis, isn't showing signs of being a vampire. So while Mavis is busy visiting her human in-laws with Johnny – and in for a major cultural shock of her own – “Vampa” Drac enlists his friends Frank, Murray, Wayne and Griffin to put Dennis through a “monster-in-training” boot camp. But little do they know that Drac's grumpy and very old, old, old school dad Vlad is about to pay a family visit to the hotel. And when Vlad finds out that his great-grandson is not a pure blood – and humans are now welcome at Hotel Transylvania – things are going to get batty!