The achievement is unlocked when you complete the traveler questline. It's a series of ten quests categorized by the game as faction quests and can be found under that heading once you accept the first quest in the sequence. It is story related and unmissable. It can be done before the main quests are completed or afterward in post-game play.
The first Travelers quest is "The Guided Hands." It is initiated when you discover Star Camp hidden in the grove of trees in the area separating Glendara and The Sidhe. There are two entrances north and south. Whether you approach this grove of trees from Glendara in the north or The Sidhe in the south, Grim Onwig will accost you. During the conversation, choose the option,"I'm interested in joining." The Guided Hands will now appear as a faction quest. The remaining nine quests in the Travelers storyline are:
--The Silent Step
--Outside the Box
--The Purloined Letters
--Thick as Thieves
Each completed Travelers quest triggers the next one in sequence until you reach the final quest, "Thick as Thieves." During this quest, you will have to pick a side between two feuding factions. You will be given the choice to go left or right. If you go left, the quest reward includes the Chariot Twist of Fate card--+1 Finesse & +6% piercing damage. If you go right, the quest reward includes the Temperance Twist of Fate card--+1 Finesse & +6% chance to evade. Either choice will lead to the completion of the questline and unlock the achievement.