Underdog presented the adventures of humble, loveable "Shoeshine Boy"(memorably voiced by Wally Cox), a modest dog who, when threats arise, assumes his secret identity of "Underdog" (complete with red union suit and blue cape). His superpowers, rather vast and varied (rather like Superman), arise once he opens a compartment in his ring and swallows his "energy pill" (about which more in a moment). He then transforms, in a burst of brilliance, to the mighty Underdog.
Also like the Man of Steel, Underdog has a friend / romantic interest in a female reporter, in the person (dog?) of "Sweet Polly Purebred". Sweet Polly, like a certain Lois Lane, often ends up in peril or in captivity, requiring rescue from her perennially rhyming hero (Underdog has a tendency to speak in verse, as in "When trouble is near I am not slow, so hip hip hip and away I go!").
And again, like Superman, Underdog has a rogue's gallery of vile foes (as of course every hero should). Most notable among them were Simon Bar Sinister (absolutely LOVE that name), a mad scientist type who constantly tries to destroy Underdog, Sweet Polly, the earth, or any combination thereof. Oh, and like his foe Underdog, Simon has a fondness for wordplay. In his case, whenever he is activating one of his nefarious devices, he prefaces it with "Simon Says...". For instance, "Simon says, go snow" when he was utilizing a freeze ray turning everyone into snowmen. All great stuff for a kid just discovering cartoons, heroes, villains, and all the accompanying tropes!
Underdog's other frequent foe was Riff Raff. A kind of wolf/person/hoodlum, Riff Raff was the embodiment of all the old mobster movies rolled into one. Usually armed with a Tommy Gun, Riff Raff knocked off banks, armored cars, etc. with flair and a pinstriped suit. And something about Riff Raff vaguely scared me as a little tyke...
Finally, what superhero show could succeed without a cool theme song? And Underdog's was one of the coolest. Actually, the whole show was pretty cool. It always seemed to have an undercurrent of impending doom; even the narrator at the show's closing contributed to that sense of threat: "Looks like this is the end...". It sure kept me coming back every week.
Oh, about the ring: it seems showing your lead character popping a pill to gain energy every week eventually troubled the tv watchdog groups. Later broadcasts edited out the pill. Not surprising, really. I always wanted a ring with secret power pill compartment as a kid. Never got it; never got a Green Lantern power ring either. Oh well...
