Pirates of the Caribbean: On Stranger Tides is a fourth movie in the Pirates of the Caribbean franchise, released in 2011. The movie features mermaids.
In London, Captain Jack Sparrow escapes from the soldiers that are chasing him and learns that an impostor is recruiting a crew and a vessel using his name. He meets the impersonator and finds that she actually is Angelica, a woman that he had seduced in a convent in Seville. Jack is abducted and when he awakes aboard, the ship is sailing, Angelica tells him that her father, the pirate Blackbeard, is cursed and he needs to find the legendary Ponce de Leon's Fountain of Youth to save his life. They force Jack, who knows the location of the fountain, to guide them. Meanwhile, Barbossa is hired by King George to lead the British crew and dispute against the Spaniards and Blackbeard who arrives first in the fountain. But along their dangerous quest, they need to find first two chalices that belonged to Ponce de Leon and a tear of a mermaid. They capture a mermaid named Syrena, and carry her to the island. She and a priest Peter fall in love on the way. The pirates trick Syrena into crying, and then go to the fountain, where Jack tricks Angelica drinking the fountain instead of Blackbeard.