A sailor on a ship in the South Atlantic eats an apple contaminated with diphtheria and infects the rest of the merchant vessel’s crew. One passenger, a deep-sea diver, tries to survive by diving into the water with his suit on, only to experience something incredible. We readers aren’t privy to exactly what that is until much later in the novel, but a clue is provided in the form of a torn piece of red suit material.
Meanwhile strange attacks are occurring in New York City involving red humanoids. And then word reaches Doc Savage's headquarters of a criminal doctor getting dragged off his ship by another red creature. But when Long Tom and Renny go missing, and then Johnny is severely injured (two broken legs and a broken arm!) Doc pulls out all the stops to get to the bottom of whatever’s going on. Doc, Monk, and Ham follow the trail that leads them to an extraordinary under-the-sea civilization, a civilization connected to one they’ve discovered before in Mystery Under The Sea, published two years previously in 1936.
This is the 67th Doc Savage novel to be published (number 83 in Bantam edition order). It was co-written by Lester Dent and Harold Davis. The year was 1938 and the yearning for technological adventure was in full swing. The Doc Savage novels have always been on the cutting edge of technology, thanks to creator and primary author, Lester Dent who liked to have Doc using all the latest gear. Frequently, he used items that weren’t even in existence yet, projecting what would be logical advancements in the near future. In this novel, however, the tech speculation goes beyond mere projection and into pure fantasy. While some explanative science is provided for how the humans can live and breathe under water using pills and a specialized gas, today's readers must really suspend their disbelief and just go with it.
Putting that observation aside, this was a fun entry in the Doc Savage series. Lots of action sequences but balanced with a straightforward mystery plot. No Scooby-Doo ending this time; the bad guys and the good guys are identified early on with no double-crossing to be found. The real focus here is on the underwater society and how it developed and operates despite the obvious barriers. Good pulpy fun. And the Boris Vallejo cover art on the Bantam edition doesn't hurt.