Commies are hinted when FBI agent Robert Clarke fears his scientist father Paul Birch is going over to "the common cause."

Ted and Jim mistake the Sapphire for the good ship Caroline. The boys, all set to sky/scuba dive for sunken treasure, land on the wrong boat, where Israeli agents (although they're not identified as so) Sylvia and Arsheim have kidnapped none other than Adolph Eichmann's personal aide, Brunner.