As the team was enjoying like at Endsville Park. They saw Billy playing annoying others with a paddleball. Ophelia made an apple pie trail that lead Billy to a giant one. There he saw the COOLBUS, as he got in. The Kids Next Door came back from a mission.
Unknown to them, Billy was inside. There they took off to the treehouse. Meanwhile, the team followed the empty pie tins to the giant pie, where they saw The COOLBUS with Billy waving at them. Bubbles said, "This isn't good."
"If Billy gets his hands on The Kids Next Door," Ophelia exclaimed, "He'll annoy everyone in the world!"
There they got onto Juliet and fled off to find him.
On the COOLBUS, Billy asked, "Do you have any more pie?"
The kids were shocked to see Billy trespassing on the bus. As they were fighting, they got a call from, "Numbuh 274" he had short blond hair covering one eye and a red suit. He said, "Sorry to be a bother kids, but The Delightful Children has activated The Delightfulization Chamber."
They needed to check it out. As they got there, they saw that Mandy was making deals with The Delightful Children into obeying her commands. Billy shouted, "Hi Mandy!"
"An intruder?" The Delightful Children asked, "We should get the ice cream men."
"Ice Cream!" Billy shouted.
He thinks that the ice creme men were in the Delightfulization Chamber and went in with Grim's scythe that he stole while he was gardening. The Delightful Children followed him. There they became, "The Delightful Reaper."
There they fought off The Delightful Reaper, but it was too much. They retreated to Sector V Treehouse, where they met the team. Cheese said as he hugged one of Numbuh 3's stuffed animals, "Pretty toy."
Numbuh 3 started to play with Cheese. There they explained what happened at The Delightful Mansion. Ophelia was shocked that Mandy is working for them. Benvolio admitted that he never liked Mandy because she's too mean and she never smiles. Ophelia decided to place a smile on her face with some cupcakes.
There she used her magic and made cupcakes with Mandy Faces on them. The others thought it was creepy.
Later at Delightful Mansion, Ophelia offered Mandy the cupcakes but refused and shoved them into her face. Then The Delightful Reaper came in and started to Attack. She attacked them with an Ice Cream Slip, a Chocolate Ball, a Cotton Candy Capture, and a Lollipop Slash, but it was unstoppable.
"Everyone bow down before Mandy!" said The Delightful Reaper.
The kids had no choice than to bow. Mandy deviously grinned and Ophelia made a run for in. Then Jasper and Bavdrot came in and were impressed by Mandy's skills. They decided to make her Jasper's apprentice. Back at the treehouse, Ophelia told them what happened.
Benvolio saw through his binoculars that The Delightful Reaper is now causing havoc amongst the kids. There they decided to attack.