(The late General Martok was replaced by a changeling at an unknown time. The threat was ended with the changeling's death.)
A clandestine operation executed by several Star Fleet officers derailed a conspiracy that stretched to the very top of the Klingon High Council itself. Martok, second in command to the high chancellor Gowron himself, was revealed to be a changeling after being shot multiple times by Klingon disruptors at the ceremony to bestow the honor of the Order of the Bat'leth. Several Star Fleet officers, accompanied by our own security chief Odo, were able to gain entrance to the ceremony and reveal the conspiracy, which threatened to place control of the Klingon empire in the hands of the Dominion.
It is believed that the Dominion wanted Odo to think Gowron was a changeling and compel him to assassinate the chancellor. This would open the path of secession to Martok, and open the highest seat in the Klingon Empire to a Dominion agent. Perhaps the most disturbing thing about this whole ordeal is that the imposter Martok was able to remain undetected for so long, despite submitting to blood tests. Another dose of insecurity has been added to the climate of fear already surrounding Deep Space Nine and the rest of the alpha quadrant caused by the Dominion threat.
On a positive note, however, war with the Klingon Empire has once again been avoided, or at least postponed. A cease-fire has been reinstated but the Klingons are unlikely to commit to a lasting peace until they have obtained a perceived victory.