AllMovie

The staff of the "Daily Planet" investigates when the scavenger ship commandeered by Captain McBain (Peter Whitney) returns from a treasure hunt with a cache of low-value pirate doubloons. It turns out that McBain is actually pulling off a scam, converting stolen jewelry into phony coins. Alas, the demented modern-day buccaneer imprisons Lois (Noel Neill) and Jimmy (Jack Larson), then forces Clark (George Reeves) to walk the plank--thereby setting up a perversely amusing situation whereby Clark reappears as Superman in order to "save" himself from drowning!