Black Book: Filament and Filigree (quest)

Walkthrough
After defeating the dragon priest Ahzidal, the Dragonborn enters one of the stone coffins and follows the passage to an altar which holds the Black Book: Filament and Filigree book.

The Dragonborn reads the book which transports to the realm of Apocrypha.

Learn the Black Book's hidden knowledge
The Dragonborn must then defeat the lurkers (×2) and seekers (×2) along the way until reaching another black book. Upon reading the book, three balls of green light appear, each corresponding to a new ability. The Dragonborn then chooses one and is transported back to Kolbjorn Barrow.

Tip: Walking in the dark reduces health, so use a spell like Candlelight.

de:Schwarzes Buch: Filament und Filigran (Aufgabe)