Hey! The King's Back!

[Raz]

I always thought the story in those 2 quests went something like this:

First, Tirion gets back the Ashbringer as per the dK questline. However, the Argent Crusade, knowing the dangers of Arthas finding out about Tirion and the Ashbringer traveling to Northrend, makes Tirion travel incognito (as how we see him in Valgarde) and the Ashbringer transported in another boat, which ends up being captured by the Vrykul.