The show starts off with a live-action interview of Abigail Lincoln (Numbuh 5) and the rest of Sector V, though separately. Even though they are now adults, they are told by an unnamed, unseen interviewer that the effects of decommissioning have been temporarily reversed so they could be interviewed on their final mission.
The actual episode begins like any other C.A.K.E.D. mission. The Delightful Children From Down The Lane (DCFDTL) are once again trying to keep their birthday cake for themselves but as usual, Sector V will make sure that it won't happen. Numbuh 1 tries to put tracking devices on them but he is spotted. After a short chase, DCFDTL get away along with the cake. Numbuh 362 arrives on the scene to tell Nigel that his sector is no longer in charge of retrieving the cake and they are to be replaced by Sector W (led by her younger brother, Numbuh 363 along with Sonia and Lee from Operation: T.R.A.I.N.I.N.G.).
Later, Numbuh 74.239 invited Sector V, W and several villains to the Rainbow Monkey Let's Learn about the Lavatory amusement park to announce that the he has the cake and he will only give it to the winner of the scavenger hunt he held.
While Sector W holds the lead, all the others except Sector V catch up with them. Then they found out that Sector W is going after the highest scoring item in the game, Father's Pipe. Sector V arrives in DCFDTL's mansion not to get Father's Pipe but to rescue Sector W. After a short argument between Numbuh 1 and Numbuh 363, Numbuh 363 loses his temper when Numbuh 1 touches him and shouts "DON'T TOUCH ME!!!", causing Father to wake up and get angry. He throws a fireball towards the two sectors which created a deep pit on the floor but missed them. He is later trapped by Numbuh 1 with a weapon called the B.E.A.R.H.U.G.G.A.H., buying them time for Numbuh 363 to grab Father's Pipe and escape. But then, Father goes into an uncontrollable rage, transforming into a fiery dragon and freeing himself from the B.E.A.R.H.U.G.G.A.H.. Numbuh 1 then inflates Numbuh 5's cap just before Father can stop him, and then he tips over and falls into the deep pit.
A singed and dazed Numbuh 363 is asked if he is okay by Sonia. Despite being saved by Sector V, he can only say: "I... I won. I got the pipe!" Furious, his teammates turn against him and Sonia gives Father's Pipe and the key to Sector W's transport to Numbuh 1. He then makes his way to the amusement park while his teammates hold Father back and show the items they got from Sector W that were given to him, putting him in the lead. DCFDTL try to get Father's pipe back but fails to do so.
Numbuh One wins the scavenger hunt and Numbuh 74.239 shakes his hand with a booger on his index finger. Just then, some sort of mold grows from the booger and encases both Nigel and Numbuh 74.239, teleporting them to a secret location.
Numbuh 74.239 reveals that the cake was just a small cupcake (and proceeds to eat it himself). He also reveals that Numbuh 1 is chosen from all KND operatives to represent Earth in the Galactic KND. Nigel's parents are present and have been temporarily recommissioned so that they can say goodbye. They also reveal that his mom was actually Numbuh 999, the first female Kids Next Door operative of the 7th Age.
Shortly after that, the rest of Sector V (although uninvited) arrive at Nigel's location. Security holds them off at first but they were later allowed to say their goodbyes. It turns out that the tracking device that Nigel was supposed to use on DCFDTL was still on. Also Numbuh 2 says that science geeks know each other's secrets which are the reasons why they tracked him down. He then gave him a bag containing his essentials. Numbuh 5 was then made the new leader of Sector V and Nigel gives his shades to her as well. But then, Father was heard coming to the secret location, but when he arrives, they are already gone.
Then, after the interview, the interviewer turned out to be Father, who says that he now knows where Numbuh 1 is. Or so he thinks... As Numbuh 5 leaves she receives a phone call on a 2X4 tech phone. She answers her phone saying that she and the others "told him everything he wanted to hear. We'll meet you up on the moon base okay? ...Oh! And Numbuh 1, welcome back.", which hinted that he had returned to earth.
Production Code: M02
Aired on: December 29th, 2007, January 21st, 2008, January 24th, 2008, July 6th, 2008
Channel: Cartoon Network Philippines, Cartoon Network North America, Cartoon Network Asia