Preemptive Strike (2014)

From the front page of the PDF:

The dark fey have made an unlikely pact with the Order of Blue Fire. These combined forces now threaten Myth Drannor, putting the alliance with Cormyr at risk on the eve of all-out war with Netheril. Can you infiltrate their stronghold and disrupt their plans? A Living Forgotten Realms adventure set in Myth Drannor for characters of the Paragon tier (levels 11-20).

Note that MYTH6-1, 6-2, and 6-3 can be played in any order. Collectively, these three adventures make up both the Fey and Flames Major Quest and Chapter Four of the Desolation series.