Volume 3, Episode 10: Lagoona and Frankie venture into the deep end of the Monster High pool to retrieve Draculaura's necklace and discover a wealth of other ghoulish treasures.
Frankie and Draculaura meet at the pool where Draculaura shows her the new necklace Clawd bought for her. Draculaura lets Frankie try her necklace on, but before Frankie can even put it around her neck, an electrical charge bolts the necklace to the Deep End (of the Monster High pool). Draculaura becomes frantic and won't even let Frankie consider going down to retrieve it. When Frankie so much as asks about the Deep End, a nearby boy launches himself outside a nearby closed glass window.
Lagoona overhears them and reveals that the Monster High pool is the deepest in the world, and that no one knows what lurks down there. Frankie still accepts the challenge despite Draculaura's frantic pleas to just let it be. Determined to make things right, Frankie dives into the pool complete with heavy scuba gear and Lagoona as her companion.
Inside the Deep End, they come across a monster which has been hoarding treasures, including Draculaura's necklace. Frankie bravely goes into its lair and shocks it, gaining not only the necklace but various other items lost by students, and the monster returns all the items that have been lost.