The lives of Lursa and B'Etor are enmeshed in the complicated, violent world of Klingon politics.  To understand their story, one must make a quick overview of recent Klingon history.  In 2346 a Klingon outpost on the planet Khitomer was destroyed by Romulans.  In 2367 Worf's father, Mogh, was branded as the traitor that aided the Romulans in that attack, an attack that had left Worf and his brother Kurn orphans.  Mogh's accuser was Duras, son of Ja'rod, a Klingon who had lived on Khitomer the same time as Mogh.  Duras was a powerful member of the Klingon High Council, and he was determined to bring down the house of Mogh.  Joining him in his efforts were his two devious and dedicated sisters, Lursa and B'Etor.

Thanks to Worf and Captain Jean-Luc Picard of the U.S.S. Enterprise-D, the truth was discovered -- Duras himself had fabricated evidence to convict Mogh and dishonor Worf's family, all to hide his own father's guilt for the Khitomer attack.  Only Worf, Picard and the leader of the High Council, K'mpec, knew this fact, and they agreed to keep the truth hidden to prevent Duras from starting a civil war.  Duras was left to believe that his secret was safe.

The following year after the murder of K'mpec, Gowron and Duras were the two candidates for the new leader of the High Council.  To assure his victory Duras attempted to murder Gowron.  He failed, but he did kill K'Ehleyr, Worf's mate, because she was on the verge of discovering Duras' cover-up of his father's crimes at Khitomer.  To avenge K'Ehleyr, Worf killed Duras.  Here began the machinations of Lursa and R'Etor.

The sisters saw their chance to avenge their murdered brother and take control of the Council.  Before Gowron was sworn in they presented Duras' illegitimate son, Toral, as the rightful successor to the Council seat.  Unknown to anyone, they had made a secret alliance with the Romulan Star Empire that gave them the resources to risk civil war to press their claim.  War indeed began, but when the sisters' deal with the Romulans was discovered, Lursa and B'Etor lost much of their Klingon support as well as the desperately needed Romulan supplies.  They conveniently disappeared.

A year later, the sisters became the target of a search by the U.S.S. Enterprise-D when an attempt was made on Worf's life at the Klingon outpost on Maranga IV.  Lursa and B'Etor were implicated but proven innocent.  However, the sisters were still working to build up their army.  It was also revealed that Lursa was pregnant at that time.  Her child has never been seen.