The way I see G.R.O.W.-U.P. Playing out after reading the episode desription and seeing the preview is;
In the first half: The Delightful children try to attack and defeat the kids next door in some sceme but fail miserably so they turn to their father. Father comes up with a master plan involving a giant battle mech (which I think is called the R.I.D.U.M according to the CN.com game) and the Age changing ray from Operation: C.A.B.L.E - T.V. That Numbuh 1 so carelessly tossed out the window. The Children put the plan into action and total the treehouse base as well as turn Numbuh 1 into an adult.
In the second half: Here's where I'm still fuzzy. I guess the Kids somehow get away but now that he's an adult Nigel leaves the group feeling either he can no longer be trusted or it just isn't right for an adult to fight as a KND. (Hopefully this episode will be more dramatic then comedy based, this situation lends itself to some great character development for Nigel/ numbuh1. ) But without their leader the rest of the KND concider giving up until they're forced into stopping the Delightful Children and Father, most likely from using the Age Changing ray on the world.
I'm really hoping for a drama based second half when it comes to what happens to Nigel/ Numbuh1. Also I wouldn't be surprised if Lasso Lass (from Operation COWGIRL) showed up again.
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