The Prakesh was the Cardassian warship in which Gul Dukat carried the civilian Detapa Council away from Cardassia during the Klingon invasion of 2372, until the Defiant came to its rescue.
The Prakesh appears in the Deep Space Nine episode The Way of the Warrior. When Sisko learns that the Klingons mean to invade Cardassia, he lets Garak overhear enough to warn his people. Dukat, by then military adviser to the new civilian government, gets the members of the Detapa Council aboard the Prakesh before the Klingons reach the capital.
Klingon ships catch and cripple the cruiser. The Defiant, sent to meet it, drops its cloak, fights off the attackers and holds its shields down just long enough to beam Dukat and the council to safety.
The rescue denies Gowron his proof that the council has been replaced by changelings, and brings the Klingon fleet down on Deep Space Nine itself.