This adventure all starts out with Krypto and Ace in pursuit of Isis, and the wily cat managing to cleverly capture both of the World's Finest Canines. Soon after, Streaky is on solo patrol and while trying to save a distressed truck, gets some help, in a round about way, from Ace's former unwanted tagalong Robbie.... who was looking for Ace. The two of them compare notes and set out in the hunt for the captured canine heroes. After some trouble in a warehouse with some cats Streaky was trying to get info out of, Streaky and Robbie end up at an amusement park..... where Streaky manages to locate the World's Finest Canines with his X-ray vision and flies to the rescue..... only to get captured himself because he got too close to the Kryptonite Isis was using to make sure Krypto couldn't break his bonds. When Robbie heads to the rescue of all three heroes, Isis captures HIM too, but the bird manages to trick Isis into putting him in a position to still help the heroes... which he does by pecking away the rope holding the Kryptonite on Krypto. Their strength restored, Krypto and Streaky are easily able to break their bonds and Streaky and Robbie end up chasing Isis into a hall of mirrors, where Robbie's blundering ends up trapping the overconfident Isis.
Now, while this WAS a very entertaining piece (especially with a legitimately clever trap on Isis's part concerning the capture of Krypto and Ace in the first place AND Streaky going into "responsible hero" mode almost immediately after he found out Krypto and Ace were in trouble [enough so to focus completely on the search AND to warn Robbie away when he went in to save Krypto and Ace]), but there were one fairly minor plot holes that kept this from being perfect. One: I would think that Streaky would be smart enough to figure out on his own that it HAD to be Kryptonite keeping Krypto too weak to break those ropes, so he would have Robbie focus on getting the Kryptonite away while HE took care of Isis. My guess is that the writer figured that the episode would have ended a couple minutes too early if they did THAT (and they also wanted to give Robbie a moment of legitimate triumph by having HIM capture Isis after he and Streaky chased her into that hall of mirrors).
Minor script point aside, this WAS, as I said, a very entertaining Streaky/Robbie showcase and, while Robbie is STILL a bit a of bumbler, he at least proved SOMEWHAT more competent than he was in his last appearance (not that it would take much, admittedly, but you get the idea).