This quest will appear in your journal when you check the "Missing Cows" poster on the notice board during the "Where Misery Gathers" quest.
A citizen of the town has apparently lost his cattle to bandits, leaving him with no means of livelihood. Listen to the farmer's story.
Rewards: 1 Silver, Medium Bag x1, Thin Hide x5

1. Speak with the despairing man
Go to the farm located northwest of the mill and talk to Bremer, a man wearing a blue vest.

2. Speak with the witnesses
Head to the next marked location nearby and speak with the herbalist you find there. Getting the information will cost you one copper coin.

Once the herbalist agrees to show you the way and mounts his horse, summon your own mount and follow him. Continue until you reach the grove where the bandits who stole the cows are holed up - Anvil Riverside Bandit Camp.

3. Read the memory on the cows' whereabouts
Start by eliminating all the bandits. Next, head to the center of the camp - where you should see a large gold urn - and take out your lantern.

You should see white-blueish spirits wandering around the camp. Observe them long enough to learn "The Missing Cow" memory.

After one of the patches, the memory should play automatically; however, if it doesn't, put on the Visone helmet and start the memory manually by selecting it from the list.

Watch the memory until the end to complete this objective and receive the next one.

4. Return to Bremer
Bremer will be waiting for you at another farm further to the north. Approach him to break the news about the fate of his cows. This will complete the quest.

The farmer was devastated. A boulder from the sky destroyed his home and his cattle were stolen. The culprits were apparently looking for something more important than cattle, a detail that makes this whole affair feel far too suspicious for simple banditry.