Once again, a special birthday cake is being made for the Delightful Children from Down the Lane. The KND take a trip to the Alamode where tour guide Numbuh 50 Million B.C. tells them about the 1800's KND operatives who were determined to steal the Annoyingly Cute Triplets Who Lived Upon the Hill's Birthday Cake, a delicious cake made by their mother. But in their attempt to get the recipe, an ice cream trap was set off, freezing over 5000 KND Operatives. It took 10 years to thaw them out, and all were decommissioned since they were technically too old to be KND. All were found except Numbuh 19th Century, until the current KND recently discovered him. After being thawed out, he's confused by the new modern era, especially with the fact there are now girls in the KND. Numbuh 86 takes offense and takes him up to the moonbase for immediate decommissioning before they're intercepted and captured by Father's Ice Cream men. Meanwhile, Father has his latest cake prepared in deep space, and he discovers the Annoyingly Cute Triplets' Mother's secret recipe on 19th Century's chest, a major treasure for him considering she was his great-grandmother. Father hopes to improve the cake for his children, in hopes of giving them the best birthday ever. But the KND mount a rescue to save their comrades.moreless
When the Delightful Children From Down The Lane frame the Kids Next Door for raiding Santa's workshop, the KND must battle Elfa Strike to clear their names and find out what's really going on this Christmas.