The DLC opens up the city of Fargrave and the Deadlands zone, which includes new quests, delves, and world bosses.
When exploring the Deadlands, you’ll encounter the vicious followers of Dagon and those few who’ve eked out an existence in this hellscape. With new delves to investigate, world bosses to vanquish, and a host of stories to experience, the Deadlands is a world unlike any other in The Elder Scrolls Online. Luckily for you, you can find refuge beyond Dagon’s reach.
A player hub and “safe haven” in a realm between realms, the mysterious city of Fargrave is home to both mortal and Daedric residents alike, living and working in relative harmony. This bizarre city serves as the base of your operations as you explore and continue your adventures.From the Official ESO site.
The Deadlands is available in the Crown Store or for free if you are an ESO plus member.