The video above is the The Witcher 3 Wild Hunt The Sunstone Main Quest Walkthrough and shows how to complete The Sunstone, the quest featured in The Witcher III: Wild Hunt.
The video walkthrough covers the following objectives:
(Optional) Ask Crach where Ermion is.
Talk to Ermion.
Talk to the bard known as Eyvind.
Return to Yennefer.
Find and talk to the pearl diver.
Return to Yennefer.
Find out if Avallac’h is hiding something.
Sneak onto the emperor’s flagship under cover of darkness.
Meet Philippa in the elven ruins.
Travel to the island where Avallac’h’s laboratory is located.
