Ep 4. Operation: F.O.U.N.T.A.I.N.

In Codename: Kids Next Door season 3 episode 4, titled "Operation: F.O.U.N.T.A.I.N.", the five operatives of the Kids Next Door embark on a mission to stop adults from stealing the Fountain of Youth. The F.O.U.N.T.A.I.N., or the Forever's One Universal Notion That All Is Now, is a legendary fountain that grants eternal youth to whoever drinks from it, and it is located beneath the adult sector.

Numbuh One, the team leader, briefs his teammates on the mission's objectives and assigns them roles. Numbuh Two will pilot the team's plane, Numbuh Three will use her rainbow monkeys to distract the adults, Numbuh Four will be the team's muscle, and Numbuh Five will be the tech expert, hacking into the adult's control room.

As they begin their mission, the team encounters various obstacles, including laser security systems, guards, and traps. However, they are able to overcome these challenges using their unique skills and teamwork. They eventually reach the F.O.U.N.T.A.I.N. and discover that the adults have already extracted the fountain water and are planning to use it for their own purposes.

With time running out, the Kids Next Door must find a way to stop the adults and save the fountain's powers. Numbuh One comes up with a plan to flood the adult sector with a potion that will turn them all into babies. However, they must first find a way to get the potion into the adult's water supply.

Using their various gadgets and tools, the Kids Next Door make their way to the water supply room and successfully spike the water with the potion. As they make their escape, they are confronted by the adult's leader, Father, who has become a baby due to the contaminated water.

In a surprising turn of events, Father reveals that he has been trying to steal the fountain's water in order to cure his own aging condition. The Kids Next Door sympathize with Father's plight and allow him to take a small amount of the water, as long as he promises to leave the rest alone. With their mission accomplished, the Kids Next Door make their escape and return to their treehouse base.

"Operation: F.O.U.N.T.A.I.N." is a thrilling episode that showcases the Kids Next Door's bravery, ingenuity, and teamwork. It also raises important questions about aging and our society's obsession with youth, while highlighting the importance of respecting other people's wishes and choices.