This Western has some of the appeal of an Egyptological adventure, as the Three Mesquiteers — Stony (Robert Livingston), Tucson (Ray Corrigan), and Lullaby (Max Terhune) — become involved with solving the murder of a scientist who had escaped from a cult that had captured him and a colleague while they were looking for a lost city. To find the culprit, the boys join an expedition organized by Betty Marsh (Mary Russell) to find her father, the remaining missing scientist. Despite attacks by the cult’s members and treachery within the group, they make their way to the titular skull — but what will they find there, and will they be able to bring the guilty to justice? Atmospheric, with plenty of action, though the suspects get perhaps too little screen time for the revelation of the bad guys to be as effective as it might have been.

  Recommended. Otto finds this one pleasing enough to relax.

Movie 497 for 2021.