The plot is pretty standard serial, in that Science Associates is losing members to violent death left and right. One scientist named Dr.Millard is seemingly killed but instead hooks up with fellow egghead Jeff King and they relocate to a cool cave lab where he pretends to be dead while King as himself and as Rocket Man (using the Millard invention of an atomic backpack rocket) tries to solve the mystery. There's a young sidekick and the usual gal reporter. All the other scientists are suspects but as they themselves continue to be killed the list gets shorter and shorter.
|(Title of feature version of the serial)|
UPDATE: As it turns out it was nearly nine years before I got around to watching it again. The movie still holds up extremely well, with a brisk pace to the chapters which are filled with vintage Republic serial fisticuffs. I'm always amazed that no matter how often someone gets the drop on someone else in these little adventures, they always lose the advantage and fist fight breaks out. I still don't like the ending -- the destruction is way off the scale to way folks respond to it, but overall this one is a winner.