This mystery can be found in the centre of Lincolnscire, just east of Lincoln in AC Valhalla.
Speak with the Anglo-Saxon Man and Defeat the Bandits
As you approach the man cowering on the road you’ll hear him complaining about a burning pain. When you speak with him he’ll attack after a brief response, now revealed to be a Man at Arms joined by a small group of bandits. You’ll need to defeat all of them to complete the mystery. You shouldn’t find this group difficult to eliminate, the main thing you’ll need to take note of is that the Man at Arms will parry most of your ranged attacks. You should also be careful to avoid the bandits throwing dirt in your face, as this can catch you off guard and leave you vulnerable to multiple attacks. If you’re caught, just dodge or roll away until the dirt is gone.