Daph found me last year's season of a Dutch reality show with English subs and I just finished watching it and I'm completely obsessed omg it's the best concept I've ever seen for a reality show.
It's called Wie is de Mol, and essentially a group of people try to complete a bunch of puzzles and challenges for money, but the twist is that one of them is THE MOLE, who's secretly trying to sabotage everything for the others. The finalists win if they can guess who the mole is, the mole wins if they fool everybody and stop them from earning money for the prize pot. It's INCREDIBLE, I've just absorbed a whole season in two days, the editing is amazingly well done to keep you guessing about the mole. I figured it out, but only in like, episode 7 or 8 out of 10, and honestly, I wasn't completely certain I was right even at the very end. The next season just started, and I'm so excited to watch along in real time and try to puzzle out this year's season as it goes!