This is Book 2 in the high fantasy Agents of the Crown series. Please start with Book 1:
https://www.youtube.com/watch?v=9zIl6XEli0g
Blurb:
Recently appointed Crown Agents Jev and Zenia must prove that they're worthy of their new jobs and young King Targyon’s trust.
Their mission?
To research the strange “disease of the blood” that killed Targyon’s three cousins and left him unexpectedly ruling an entire kingdom at barely twenty years of age.
There are just a few problems. If someone was responsible for creating that disease, that person could still be in the city, forcing Zenia and Jev to deal with someone very smart and very dangerous. Meanwhile, since Targyon has the same blood flowing through his veins that his cousins had, he’s at risk of becoming the next victim. And as it so happens, Jev shares some of that blood too. Might he become a target before Targyon?
When Jev and Zenia signed on for this job, they didn’t realize how deadly it might become.
You can pick up forever copies of these audiobooks (or the rest of the series) at Audible, Amazon, Chirp, Google Play, Kobo, Apple, and other audiobook stores:
Audible: https://www.audible.com/pd/Blood-Ties-Audiobook/B07JK97VZB
Amazon: https://www.amazon.com/Blood-Ties-Lindsay-Buroker-audiobook/dp/B07JKFK2YX
Google Play: https://play.google.com/store/audiobooks/details/Lindsay_Buroker_Blood_Ties?id=AQAAAEBM0nOSLM
Apple: https://books.apple.com/us/audiobook/blood-ties-agents-of-the-crown-book-2/id1440495691
Chirp: https://www.chirpbooks.com/audiobooks/blood-ties-by-lindsay-buroker
Kobo: https://www.kobo.com/us/en/ebook/blood-ties-102
Blood Ties is written by Lindsay Buroker and narrated by Vivienne Leheny.