Last issue Bob escaped from the freighter with Margery Noel, the spy, as captive --
Hydroman [Bob Blake]; Joyce; Harry Thurston; Dave (by-stander); Margery Noel (villain); Paul (villain, spy); Karl (villain, spy); Josef (villain, spy); Hermann (villain, spy); Wilhelm (villain, spy); Ludwig (villain, spy); Oscar (villain, spy)
Hydroman releases Margery Noel when policemen appear on the scene to capture him. Returning to his apartment, Bob brings Harry and Joyce up to date on the situation. Suddenly a group of spies appear on the scene with one purpose in mind. However, Hydroman has a countermove in mind that will draw out the real crooks.