"In honor of our fathers" - "One Khan, One Clan" [Campaign 3, Mission 2]

Help...where can I buy this talisman? I can't seem to find it. Please advise.

Are you referring to a talisman for various travel spells? You build a traveler's hut in the castle and purchase it for money and resources within the castle. You can buy a cheap one for a single spell, or a more expensive one for 2, 3, or 4 spells, respectively. You can purchase it near the slave market; it appears there after the hut is built.