During Night at the Library, you will gain access to a NPC called Swift Solutions. Doing these fetch quests will reward you with Tokens of Gratitude, which you can use to seek out new citizens for Evermore. Yung Mein is one such citizen and it will cost you 10 Tokens to get this sidequest. Once you purchase it, all you have to do is speak with Yung Mein in Goldpaw (just outside of Fortune Square) to complete the quest.