The Changeling Soldier - Shona Husk

Rather short...

 

The h is a fairy who left Annwyn centuries ago. The king is dying apparently and she's feeling the urge to go home. There's just one last job...

 

The H is a changeling whose sister knows just enough about fairies to be dangerous - to everyone - and she's figured out somehow that the h is a fairy so has laid a trap.

 

Never make a deal with a fairy. She gives up her brother without a thought, the h takes him home with her (literally), and well, the sister gets fame alright - being accused of kidnapping and murder of a well-known fashion designer will certainly put you on the front page.