Chapter 9: Tightening CoilsWalter Hollbrand, the son of the famous surgeon Dr. Gordon Hollbrand, has disappeared. Jimmy Christopher suspects the same criminal mastermind who's snatched Z-7. After searching Dr. Hollbrand's office, he discovers one item removed by an unidentified suspect. Once again, the suspect escapes. Operator 5 assigns Diane Elliot, ace reporter and his love interest, to look after the steel magnate Martin Evarts.
Not a whole lot of information, so far, on who this masked man happens to be, or what is his motivation.