Mysterious Formula | Mission 5 - Caught in the Trap Styx: Shards of Darkness Guide

The two dwarves will reveal the location of the formula

During your attempt to reach Ephron (in case you've chosen to board the airship) you can stop on the roof and eavesdrop on two dwarves talking about a mysterious formula, which is definitely worth a small detour. If you've chosen to leave by the boat, stand on the inn's roof and listen to the conversation.

The formula can be found in the room at the second floor of the inn

The formula can be found in one of the rooms in the tavern, which can be accessed through an opened window. The formula unlocks a special elixir that kills your scent for 3 minutes, making the dwarves unable to detect you through scent.