From the introduction:
No campaign is easy for a Dungeon Master to run but the Rime of the Frostmaiden Companion ("Companion" for short) is devoted to making it easier and more satisfying for you to run. By providing new hooks, variants, flavor text, as well as any referential information for creature statistics or magic items, this supplement should make for a faithful companion to keep at your side.
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The Companion is quite formulaic; every chapter is designed to be easily digestible, whether you're a veteran reader or just diving into it mid-campaign.
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Chapter 2 sees the adventurers striking out from Ten-Towns to explore the unforgiving wastes and rid them of potential threats to Icewind Dale. Take your time with this chapter, because once it's over, the campaign is locked into a schedule: the adventurers have to invade Xardorok's Fortress in Chapters 3 and defeat his dragon in Chapter 4.