A Deep and Creeping Darkness | Candlekeep Mysteries DM Guide 

I’m currently running the book as a full adventure and here’s what I did: First of all, reading the whole book in advance and writing a story to tie everything together seemed too daunting, so I did kind of a leap of faith, hoping everything would be allright. I kept Matreus from the first adventure, and made him establish a bureau inside of Candlekeep investigating odd cases caused by books, under the city rulers’ orders. In order to extend their stay inside Candlekeep and make some money, my players gladly agreed being part of the bureau. Using Fistandia’s Mansion as their base of operations, they are the FBI of Candlekeep now and are having an absolute blast. The only real challenge I’m facing as a dm is that some of the adventures need some plot hook adjustments to fit into this setting, but nothing you can’t handle. Hopefully this sparks some ideas!

@@keremyakutlu255 Thanks! Great idea, yeah I was trying to think of why the players are there, or why to keep doing these quests. I was thinking the players are at Candlekeep for some backstory reason, then at the tavern an NPC talks to each one about putting a team together to solve a mystery about a book and a cursed town. Then some myconids appear in the tavern and there's a fight which bonds the players. Then it's just what you described after that! I'll probs use Matreus there and not kill him off.

I have done something Similar. In mine, BookWyrm actually ran a covert strike force to seek out mysteries and be an offensive arm for the mysteries Candlekeep gets involved in. BookWyrm meets the players during the 2nd level mission. He states that he would task The Librarians with investigating the Gingwhatzits, but they have not yet returned. The players volunteer to investigate and BookWyrm pays them and sets them up with what they need, becoming their patron. The party later finds out that The Librarians have not returned for over a year and are presumed dead. They are now an investigative force for Candlekeep and also use the Mansion as their headquarters.

i'm currently running some of my viewers so I don't want to spoil my plans, but yes I did tie in that final boss very early in the campaign

The final adventure does have a crisis that has been building up over the course of several months, so it would be easy to drop rumors of her effects throughout the earlier levels. What I decided to do was to tie Xanthoria to the eldritch creature Gaernoo from the Level 7 adventure, and use him as a recurring problem as he gives all sorts of villains information to help their vile schemes (as he's a god of doing evil things for knowledge and doing evil with knowledge). I added a fungal theme to his stuff (depicting his knowledge like fungi that require dead things to grow on) and made the druid lich his most powerful servant, spreading his corruption throughout the minds of the land.