ESO Chronological Timeline Guide - Best Way to Play the Story

Greymoor will introduce a new story arc, the Dark Heart of Skyrim storyline. It already starts in the prequel and finds its continuation in Western Skyrim.

Jorunn the Skald-King has dispatched agents to Western Skyrim to investigate and deal with a threat not only to Skyrim, but to all of Tamriel. Find the Skald-King's agent in Solitude, the capital city of Haafingar Hold.

You will need to meet with the agent, in the capital city of Western Skyrim's Haafingar Hold. The agent is investigating a potential threat to not only Skyrim, but to all of Tamriel, because supernatural Harrowstorms plague Western Skyrim, and dark beasts, led by a powerful Vampire lord, devour souls to further their mysterious plans.

The Dark Heart of Skyrim is the fourth main story arc of ESO, following on from the Season of the Dragon. It spans multiple content updates, covering the entirety of 2020's content releases.

You can usually find the agent in the Fighter's Guild of any starter cities, or get the quest from your Collections tab in-game.