Red Dragon by Lindsay Buroker

Scarcely two weeks have passed since Princess Syla bested Captain Vorik and returned home with a magical sky shielder to protect her kingdom. Is the powerful dragon rider holding a grudge? Will his people come after her and try to steal or destroy the shielder?
Syla may find out sooner than expected when Vorik shows up in her harbor with his general and chiefs. They claim to be on a diplomatic mission, but she suspects they have treachery in mind.
As much as she would like to trust the handsome and charismatic Captain Vorik, especially when he smiles at her instead of scowling, she has to be wary. Her feelings for him might make him her most dangerous enemy.