The video above is the The Witcher 3 Wild Hunt The Mystery of the Byways Murders Witcher Contract Quest Walkthrough and shows how to complete The Mystery of the Byways Murders, the quest featured in The Witcher III: Wild Hunt.
The video walkthrough covers the following objectives:
Talk to the commander of the Nilfgaardian patrol.
Find out what happened in Byways.
Deal with the ghouls prowling the village.
Find the surviving villagers.
Explore the village.
Follow the scent of blood.
Explore the tunnels under Byways.
Kill the ekimmara.
Collect an akimmara trophy.
Talk to Bytomir.
Report back to the Nilfgaardian patrol commander.
