For every single fan of Captive Prince, this story is a precious gift. In order to enjoy it to the full you should read 3-book Captive Prince series first. There are a lot of inside jokes, in fact the whole plot is an inside joke. 
 I really hope this author will give us another series soon. She's a master at creating unforgettable characters. Charls, dear Charls. Even Alexon... 
 Now I hope the Captive Prince fanfic will be inspired by this short Charls' story.