5 days after the flying broom incident and after clearing Winnie's name, willie started to hang out with vivien so they can get to know each other better and they did so secretly otherwise winnie will be pretty mad at willie for talking to strangers.

When winnie gets grounded for something she didn't do it's up to dennis to clear her name without getting caught and unexpectedly gets help from Winnie's younger brother

Dennis winnie and Willie were playing outside then they saw a young witch the same age as willie flying by on a broomstick and accidentally ran into willie and when the broomstick landed something unexpected happens.

When Dennis was flying outside at night for fresh air he runs into a young werewolf boy that ran away from home after Wayne and wanda had a massive fallout.

This takes place after hotel Transylvania 4 Dennis and Winnie were having a sleep over at Winnie's house and Winnie began to have a nightmare about a year ago on Dennis's 5th birthday party, winnie is hiding something and is too embarrassed to tell dennis because she's worried that it will probably destroy their friend ship.