Sneaking through the base of a master assassin, one with as much skill and supernatural power as you. He kidnapped you, took your fancy gear and tossed it down a refinery pipe while tossing you into a drain. And he's the guy who murdered to person you cared most about and subsequently framed you for it. You have every reason to want to kill him.
I crept through the base, stalking his assassins as they went about their daily routine. Many were caught unawares, knocked out, and tossed in a closet somewhere, until finally, I reached his inner sanctum. He knew I was coming for him. I had to. There he waited for me, waiting to fight the epic duel between two master assassins. But he was distracted. He was certainly on watch, but it could be said he was
too vigilant, and it distracted him from his surroundings.
A moment of vulnerability. It allowed me to creep right into a blind spot outside of his and his guards' view. And there, right behind him, I reached out and...
...nicked his wallet. And the key I needed to escape. Then I snuck out, leaving him there, using his key to steal more loot and then reach the sewer tunnels to make my escape away from his base.
Dishonored. I think that the world this game takes place in would make a great tabletop setting.
Also gotta give some serious credit to the late Empress Kaldwin. She was popular enough that even the assassin who killed her was pissed off enough about it to want get avenge her.