Operation: R.E.T.U.R.N. (Returning Entirely To Universe Right Now)

Plot Summary
Previously right after Operation: I.N.T.E.R.V.I.E.W.S. (It's Now The Exra Really Very Interesting Wrap-Up Story), ever since Numbuh 1 left to help out with the Galactic Kids Next Door Operatives, Numbuhs 2, 3, 4 and 5 are hoping that he'll return somehow. Eventually, Numbuh 1 returns to rejoin them as their team leader and the Delightful Children also return to sneak up on them and cause more trouble like usual.

Transcript
Operation: R.E.T.U.R.N. (Returning Entirely To Universe Right Now) transcript