Danny goes undercover to see just how dangerous the threats of neo-Nazi group really are.
This episode struggles in a lot of ways, almost breathless in wanting to be "hip" and show imminent danger but failing in most every respect. The idea that the group actually occasionally dresses as WW II German Nazis is rather hard to swallow, and the scripted racist rhetoric is too dated and quaint even for this series. James MacArthur is almost always a better actor when sticking to plot-related situations, he comes off very forced when trying to play a broader character almost every time. It's quite noticeable in the scenes where he tries to convince Stoner of his sympathy for the "cause".
For all the "danger" implied by the neo-Nazis in this episode, very little is actually acted on - even when Danny is uncovered, the threat is weak. In the same vein, the group's various plots to discredit the Hawaiian political candidate are either hopelessly convoluted or extremely tame. It may have been better to write Stoner as having deep-seated psychological issues and play that angle.
Missing the sense of suspense of a credible threat and saddled with outdated and unrealistic dialog, this episode is a good example of how the "Hawaii Five-O" formula was not adapting sufficiently in its final seasons.