In the second season episode "The Emissary" she assisted the Enterprise with recovering a group of Klingons that had come out of cryogenic stasis unaware of the treaty between the Klingons and the Federation. She also rekindled her relationship with Worf and it was then that their son Alexander was conceived.
K'Ehleyr would return to the Enterprise a few years later in the episode "Reunion", bringing her son Alexander in tow. Alexander was not yet aware that Worf was his father. The reason for K'Ehleyr's visit was to aid in the Rite of Succession, a ceremony that would determine the next leader of the Klingon Empire following the death of Chancellor K'mpec.
K'Ehleyr was aware of some of the details behind Worf's discommendation from the Klingon Empire, but certain records regarding his trial had been sealed. When Captain Picard was unable to reveal all the details, K'Ehleyr conducted her own investigation and learned of the connection between Ja'Rod, the father of would-be successor Duras, and the Romulans. Ja'Rod had conspired with the Romulans and brought about the infamous Khitomer Massacre and Duras had later shifted the blame to Worf's father Mogh. It became apparent that Duras' house was still in league with the Romulans and that they were planning to usurp the Klingon throne. Duras discovered that K'Ehleyr was on the verge of exposing his scheme and so he attacked her in her quarters on the Enterprise, stabbing her repeatedly. Worf and Alexander later found K'Ehleyr on the verge of death, lying in a pool of her own blood. She revealed Duras' treason to Worf just as she slipped away in his arms.