With its swaying palms and breezy ocean vistas, as vicariously relaxing as anything on film, How Stella Got Her Groove Back starts like a study of rejuvenation, a restorative experience for both the title character and the viewer. But like the book on which it was based, Kevin Rodney Sullivan's film loses some impact when it retreats home to the United States and becomes a melodrama, tackling such diverse topics as disease, family, and May-December romance. To be sure, Angela Bassett and Whoopi Goldberg bring oodles of sisterly chemistry and screen presence, and Taye Diggs, in his film debut, looks exquisitely at ease as a studly charmer. Watching these elements intermingle against a gorgeous backdrop would have been excuse enough for a film. Perhaps Terry McMillan's book should have stopped there, because once Stella relocates her groove, the plot slides into the rather ordinary story of unlikely lovers trying to overcome their differences. The movie has the strange feeling of reaching its catharsis and then pursuing its plot threads past the point where the credits should have rolled. Minus a half-hour from its 124 minutes, How Stella Got Her Groove Back would have been more effective escapism, while still able to touch on some of the deeper concerns of these women. With its additional agendas, it's still worthwhile -- it's just not quite as groovy.