Reign or Shine by HJ Welch

A secret prince needs: a lost tourist to save.

Prince Cassander is on vacation from his overdeveloped sense of duty. While hiding out as simply ‘Cas’ in the Rosavian capital, he rescues a gorgeous, distressed American tourist. Matty has no idea that Cas is second in line to the throne. And with only two weeks together to explore the sparks between them, he doesn’t need to ever find out.
New Yorker Matty Doyle is a fish out of water, taking care of his niece and mending his broken heart. When Cas rescues him, the handsome stranger coaxes Matty out of his shell and he throws caution to the wind. Nobody knows him here. Would it hurt to live a little for once?
But a prince can’t stay secret in his own country for long. Cas would give anything to protect Matty from reality, but how can this fantasy together continue when they belong in different worlds?