Count Dracula, the proprietor of Hotel Transylvania, is feeling lonely and longing for companionship, despite the thriving business at his monster-exclusive resort. His daughter, Mavis, misinterprets his sadness as work-related stress and decides a family vacation on a luxury monster cruise would be the perfect opportunity for him to relax and spend quality time with his family and friends. The cruise, which promises to cater to all their distinct monster needs, embarks from the Bermuda Triangle heading to the lost city of Atlantis. Dracula's pals, including Frankenstein, the Mummy, Wayne the Werewolf, and Griffin the Invisible Man, are all in tow, ready for a fun and frolicsome adventure at sea.

As the monsters indulge in all the ship's amenities and exotic excursions, Dracula falls for the ship's enigmatic human captain, Ericka, who hides a secret that could threaten the monsters' very existence. The chemistry between Dracula and Ericka is undeniable, but his daughter Mavis, who is overprotective of her father, grows suspicious of Ericka's intentions. Amidst the fun activities and the burgeoning romance, dark forces plot in secret, looking to disrupt the monster harmony and bring about an old and dangerous legacy to fruition. As the voyage continues, hidden agendas are slowly unveiled, forcing the monster group to confront challenges that could alter their lives forever.