It's 2002 and Puchi Lavoe (JENNIFER LOPEZ) is looking back at the life and times of her husband, Héctor Lavoe (MARC ANTHONY), who was once king of the world of salsa. Flashing back to 1963, Héctor Perez is a young singer who performs with his father (ISMAEL MIRANDA) on the streets of Ponce, Puerto Rico. Yet, he knows he must travel to the U.S. if he wants to make it big, so against his father's wishes, he arrives in New York City in 1963.
There, a young worker, Eddie (MANNY PEREZ), gets him into a club and Héctor is immediately entranced by the scene. It isn't long before he's up there on the stage, doing his thing, and drawing the attention of Johnny Pacheco (NELSON VASQUEZ), a famous bandleader, and his record label partner, Jerry Masucci (FEDERICO CASTELLUCCIO). Johnny sets up Héctor with another musician, Willie Colon (JOHN ORTIZ), and the two are soon a big hit, drawing in the crowds and, in Héctor's case, with his new last name, the attention of a pretty clubgoer by the name of Puchi.
The two are soon an item, but her introduction of him to drugs soon backfires as he dives into them with abandon, including the use of heroin. Nevertheless, they get married, eventually have a child, Tito (played at successive ages by JARED EVERLETH, BERNARD HERNANDEZ and CHRISTOPHER BECERRA), and he continues to experience great success in the new music genre known as salsa.
Yet, his drug habit becomes too cumbersome, eventually putting a strain on both his career and his relationship with Puchi. From that point on, and as she tries to help while also enabling him, he experiences the highs and lows of being a famous singer.