Murder and royalty didn't mix. Princess Helena had only a distant claim to the throne, but when her friends and lovers began turning up dead, Buckingham Palace demanded to know the reason why. The princess, it appeared, had a wildly wicked streak. It might have been elegant entertainment indeed, squiring Her reckless young Royal Highness through her dutiful official days and licentious London nights. But Supt. Perry Trethowan, Scotland Yard, had precious little time tor pleasure it he meant to stop a cold-blooded killer intent on blue-blooded murder and prevent the scandal that would shake the nation.