Assassin's Creed Odyssey

The Wolf And The Snake
Episode 3 consists of these story segments:

1. Onwards to Phokis
2. Of Visions and Visionaries3. Snakes in the Grass
4. The Serpent's Lair

You will get this achievement after "The Serpent's Lair" segment. You just need to attend the secret cult meeting, learn what they're up to, and get out of there. The achievement pops after your post-meeting talk with Herodotos.

^{I still say the cult meeting in the game makes me think of the secret orgy scene in the movie, Eyes Wide Shut (1999).}