The Assassin and the Healer seems to be the shortest of all the novellas. In this one we learn that Celaena is being sent to the Red Desert as punishment for disobeying Arobynn. She gets stuck waiting for a ship to take her there in an empty, boring town called Inning.
There we meet Yrene, a healer who was traveling to learn more about healing when she ran out of money in Inning. She’s a nice character, has her flaws but is strong when it’s something she believes in. Celaena was an ass, frankly, for most of this one but at the end she shows who she is and reminds you why you like her.
All in all, it’s a quick read and enjoyable if you have enjoyed the other books by Sarah J. Maas. It is, however, just not that exciting for the most part.