This quest begins immediately after Flann over Ireland. Now that Flann has been crowned, it’s time to meet him at Durrow, located west of Dublin.
Search the Stashes at Inchroe’s Bog
When you meet with Flann at Durrow he’ll tell you that a sacred book, known as the Book of Kells, has been stolen by local Danes. The Danes are from Dublin, so Flann uses the theft as an example that Barid is unable to keep his own people in check. Eivor informs Flann that he will get the book back, if it will restore faith in Barid’s hold on power.
To find the book, you’ll need to travel to the bog camp at Inchroe, located just north of Durrow. When you arrive at the camp you can use your raven to identify three possible stash locations where you can search. You can go through these if you wish to uncover additional documents, but they’re not necessary for completion of the quest. If you want to be in and out of Inchroe as soon as possible, go to the roundhouse located in the north of the camp and enter it to trigger a cutscene with Thorstein. Eivor will threaten him until he reveals where the book is being kept, at Boyne Tombs.
How to Get the Book of Kells at Boyne Tombs
When you reach Boyne Tombs you’ll find that the entrance is blocked by a barricade of stones. If you have the Incendiary Powder Trap ranged ability, you can use this to destroy the barricade as soon as you arrive. Alternatively, you’ll find a fire pot on top of the tombs, along with a few bandits. If you don’t want to destroy the barricaded entrance from outside, you can use your raven to identify the location of a wooden plank which is blocking entrance to the tombs from above. Shoot this and then drop down to enter the tombs.
Once you’re inside Boyne Tombs, turn north and take the key from the main room that you find here. You’ll need to kill a few bandits before you can move on peacefully, but they shouldn’t pose much of a threat. When you have the key, continue southward until you find another room with a couple of bandits. Kill these and then use the key to open the door to the chamber where the Book of Kells can be found, along with a few chests of treasure. Explore the cracks in the walls to loot the treasure in the tombs, including one containing the Druidic Armor, and then exit the tombs to return to Flann with the book, thereby completing the quest.