The king [Pierce Brosnan] is Louis XIV, the Sun King; his daughter [Kaya Scodelario] is the illegitimate rebellious musical Marie-Josèphe, being raised anonymously in a convent. Louis wants to live forever, to serve France better, so has a mermaid captured in order to extract immortality from her heart. He also wants better music, so has his daughter brought to Versailles. Daughter and captive mermaid conspire for freedom.
This is based on Vonda McIntyre's Nebula Award winning novel The Moon and the Sun (which for some reason I seem not to have not read), although with significant changes to the nature of various relationships.
The action moves along fairly well, although there is some fairly lazy narration to set the scene. Pierce Brosnan plays an interesting part with gusto: he is a king with ultimate power who is nevertheless acting in (what he deems to be) the best interests of his country. Kaya Scodelario is suitably feisty as the rebellious but naive convent girl, not knowing why the king is taking an interest in her. Others are there to move the plot along its see-sawing arc.
Entertaining, but a bit disjointed. I suspect the book is better.
reviewed 21 February 2026