When Angel Scarlett, Fairy Cora, and Princess Daphne visit Lily the Ladybug's Boutique to look for Halloween costumes, they find Lily has left aside three special masks for them. The ladybug informs the sisters that they must wait until noon on Halloween to try on the mysterious masks but assures them they will have the best costumes in all of the land of Harmony.
The sisters can hardly wait, counting down the minutes on Halloween until they can don their curious masks. When the time comes, they learn their secret masks are enchanted, and the girls are magically transformed into the costumes of their dreams.
After a fun outing Trick-or-Treating, the little monster, witch, and ghost - or sisters - agree that this was the best Halloween of all.