Complex sentence: It is based on and serves as a prequel to the 2012 film "Hotel Transylvania", taking place four years before the events of the first film, focusing on the teenage years of Mavis and her friends at the Hotel Transylvania.
Split into simpler sentences: It is based on and serves as a prequel to the 2012 film "Hotel Transylvania". The series takes place four years before the events of the first film, focusing on the teenage years of Mavis and her friends at the Hotel Transylvania.