Harry and his friends attempt to infiltrate a luxury cruise ship to rescue Ai. However, a trap had been laid and they are captured. Helplessly, they are forced to watch as Ai, under the influence of a strong aphrodisiac, is gang-raped before a crowd of spectators.

What anime is so good that you think non-anime watchers should still watch?

Most starter anime series would fall into this category, as they are used to capture the hearts/minds of non-anime viewers and, hopefully, start their new found passions into anime. Sarah Tison's answer to What are the top 5 animes I should watch? Sarah Tison's answer to What is the anime you would recommend to get an outsider in to it? You got one shot, or they'll hate it forever. Sarah Tison's answer to How do you differentiate between good and bad anime? What makes an anime “good” or “bad”? As you can see with the various lists above, the quality of anime can not simply be broken down into recommendable shows because everyone’s notion of what makes an anime good differs.
After all what started it for me is probably different than how other got into it: Sarah Tison's answer to Which anime did you watch that turned you into an avid consumer of anime? But regardless of what got us into anime, there are a few shows which everyone would agree are worth the watch. Hunter x Hunter (2011), Death Note, Attack on Titan, Sword Art Online, Fullmetal Alchemist: Brotherhood, and things along this sort. Are they creative recommendations? No, but that doesn’t mean you should chuck them out for consideration.
You don’t have to wow your first time viewer at the cultural brilliance integrated into your viewing tastes.
Things like Monster, Gakkou Gurashi, or Death Parade can come later if they choose to continue. Above all else, I think what people want to see is a comparison like this: But it can be really hard to do this sort of thing because of the drastic styles from TV shows to anime series.
They may have similar themes, but you have to know what you are recommending to someone and really play it off their tastes, otherwise you may not get anywhere.