As the Monster Ball Homecoming Night comes to an end so does the mystery of finding who is the Formal Phantom. Was the monster behind the chaotic night brainwashed into sending ghouls and boos to a different dimension? Frankie uses their brain and clues to find one monster, or maybe more.

Everything the Boo Crew have done so far hasn't worked, but maybe Clawdeen's backup plan to use a book with dangerous spells of dimensions and disasters can help. But they have to hurry and solve this case before the Monster High disco ball drops. Heath Burns, Frankie, Cleo, Draculaura, Clawdeen, Lagoona, or any one of the monsters can be the key to fixing this freaky Homecoming night.

After Cleo gets sucked into another dimension, she finds Headmistress Bloodgood, Deuce, Clawd and Draculaura there. As the shadows creep toward them, an unlikely hero appears to rescue them. But could this mean leaving behind a monster in this in between world?

Frankie, Heath, and Lagoona make a great team which brings them one step closer to finding the Formal Phantom at the Monster Ball. Now it's time to find a totally normal and not sneaky explanation to why a certain ghoul hasn't been completely honest. Can Frankie and Lagoona find the answers to reverse a curse?

Frankie and Deuce are still at the Monster Ball dance and try to keep things under control while Clawdeen and Toralei find the Formal Phantom. When Lagoona tries to help, another suspect is revealed and causes things to heat up. The evil entity strikes again and leaves a cryptic message. Can the rest of the Boo Crew solve the riddle, or will the portal take another helpless soul?

Clawdeen and Draculaura get help from an unlikely suspect, Toralei. The three of them take the earworms back to the science lab to search for clues and are surprised by what they find. Draculaura's date, Clawd, is still missing which could also make him a suspect and the portal comes back to take more ghouls and boos into another dimension.

Headmistress Bloodgood doesn't want to cause a panic at the Monster Ball Homecoming dance, but things are getting creepier with the school under attack. Draculaura and Clawdeen work together when the floor becomes lava and arrows are flying at them. The two ghouls get surprised by who, or what, could be behind this mystery that is sending monsters to another dimension and Toralei may be a suspect.

It's the night of the first Monster Ball Homecoming dance and Frankie, Cleo, Deuce and the rest of the Boo Crew are on duty. Someone, or something, unleashes creepy mind controlling earworms that hypnotizes Monster High. Draculaura, Clawdeen, Lagoona and the crew try to solve this mystery as the pranks continue in this new series.