Charles Aarons is one of the most sociopathic characters ever to appear on Hawaii 5-0. As a software developer who has his fingers in dial-up access and the underlying software systems of some of the largest corporations in Hawaii, his ability to check out and change information.
He decides to use that access to help the son of his wealthy employer beat a murder charge. And the son is guilty ... we saw him commit the crime. So did the victim's neighbor, whose reputation is almost ruined by meddling in telephone records.
Aarons' effort don't simply stop at hacking, though. He's willing to commit murder, himself, to advance his plan to gain $200,000. It seems like a paltry sum, and even those in 1974 it was about 10 years of a nice salary, I think the payoff is a bit low for the changes he takes, including leaving his job.
The two flaws? First, the impetus which solves the case comes from what I considered to be an unlikely Mcgarrett epiphany. Those happened quite often after the first few years of the series. Second, Aarons scheme to get paid was entirely inadequate. Someone as clever as the character was made out to be could SURELY have done better, and you'll know why that's important if you watch the episode.