Often improbable, sometimes ludicrous, but frequently exciting, this is the latest attempt by producer-screenwriter Luc Besson (La Femme Nikita) to peddle his notion of a feminist action blockbuster. In this case, that means a movie in which a beautiful assassin (Zoe Saldana) runs around in her underwear (or less), kills for hire or for private reasons, tries to avenge the drug-related murders of her Colombian parents, eludes a somber FBI agent (Lennie James), beds a sensitive painter (Michael Vartan), and tries to express her feelings to him. Saldana makes this watchable, James supplies a fitful plausibility, and director Olivier Megaton (a former graffiti artist) keeps things racing along, preposterously.