Mavis and Johnny get married and things are changing in Hotel Transylvania. Drac allows human guests to stay at the hotel now too. Mavis gives birth to a half-human half-vampire son named Dennis. When he reaches the age of five, Drac becomes worried because his vampire traits are not showing yet. He asks his friends for help to educate the little one. Things get complicated when Drac's old-fashioned father Vlad visits the hotel. Meanwhile, Mavis has a culture shock visiting California with Johnny.