In "Operation: B.U.L.L.I.E.S. (Big Ugly Lunks Like Intimidating Entrapped Scaredycats", Numbuh 2 and Numbuh 4 visit an island habitat where a kid scientist keeps dinosaur-like bullies. He assures them that they are completely safe from the bullies, but it might not be just the bullies they have to worry about. In "Operation: F.I.S.H.Y. (Feline Invaders Swarm Headquarters Yearningly)", Numbuh 3's goldfish has died, and none of her fellow operatives have the heart to tell her. So while Numbuh 1 and Numbuh 5 try to get a new fish as a replacement, it's up to Numbuhs 2 and 4 to journey to the far side of the KND Treehouse to give the old one a proper burial. But with the Crazy Old Cat Lady after them, that won't be so easy.