Looking for BL manga!

So it was on my list but it got deleted and I’ve been trying to find it! So it’s about a side couple from another manga. It takes place in a desert place and the uke is in love with the main ukes guard/ servant? He also has a pet snake! Seme is more calm and reserved. They are also trying to find out something of a poison or something illegal that they don’t want to be sold?
Thank you!