King Louis XIV's quest for immortality leads him to capture and steal a mermaid's life force, a move that is further complicated by his illegitimate daughter's discovery of the creature.
| Actor | Role |
|---|---|
 Pierce BrosnanKing Louis XIV | King Louis XIV |
 Kaya ScodelarioMarie-Josephe D'Alember | Marie-Josephe D'Alember |
 Benjamin WalkerYves De La Croix | Yves De La Croix |
 William HurtPere La Chaise | Pere La Chaise |
 Julie AndrewsNarrator | Narrator |
 Fan BingbingMermaid | Mermaid |
 Pablo SchreiberDr. Labarthe | Dr. Labarthe |
 Ben Lloyd-HughesJean-Michel Lintillac | Jean-Michel Lintillac |
 Rachel GriffithsAbbess | Abbess |
 Paul IrelandBenoit | Benoit |
 Crystal ClarkeMagali | Magali |
 Kaya BlocksageDuchesse de Fontages | Duchesse de Fontages |
 Kasia KaczmarekSister Constance | Sister Constance |
 Tom MortonFirst Musketeer | First Musketeer |
 Tiffany HofstetterMother | Mother |
 Jessica ClarkeMadam Devereaux | Madam Devereaux |
| VVirginia BowersMarie-Josephe's Mother | Marie-Josephe's Mother |
 Marc de PandaIntendant of the King | Intendant of the King |
| JJorja LindsayElla | Ella |
| DDiane DuquesneCourtisane | Courtisane |
 Jean-Baptiste SagoryNobleman 2 | Nobleman 2 |
 Crispin FreemanMusketeer #6 | Musketeer #6 |