Star Trek: Generations
In 2371, Lursa and B'Etor strike a deal with El-Aurian scientist Dr. Tolian Soran: they acquire a supply of trilithium for the doctor's experiments and Soran helps them to develop a trilithium-based weapon with which to threaten the Klingon High Council. The Duras sisters steal a supply of trilithium from a Romulan outpost and give it to Soran so that he can properly research and refine it, but the Romulans come in search of their stolen property and attack the Armagosa Observatory where Soran is carrying out his work.
The sisters later retrieve Soran as well as captive Enterprise engineer Geordi La Forge. Soran sabotages Geordi's VISOR and turns it into a surveillance device, then Lursa and B'Etor later negotiate a prisoner exchange with the Enterprise: Captain Picard will surrender himself in exchange for Geordi after he has been allowed to meet with Soran on the surface of Veridian III. The exchange is made and Geordi is returned to the Enterprise, with none of the crew aware that Geordi has been turned into an unknowing spy. When Geordi returns to Engineering, his gaze passes over a monitor displaying the Enterprise's shield frequency. The Klingons adjust their ship's weapons to match and then open fire on the Enterprise, bypassing their shields and inflicting heavy damage.
In the middle of the battle, the Enterprise sends out an ionic pulse at the Klingons' Bird-of-Prey, which disrupts the ship's defective plasma coils that are connected to the vessel's cloaking device. The pulse triggers the cloaking device, rendering the Klingon ship invisible but also disabling its weapons and shields. In this moment of confusion, Lursa and B'Etor are unable to take action to save their ship as it is struck by a photon torpedo fired from the Enterprise. The ship is destroyed with all hands.