“The Way of the Warrior: Part 2” is episode two of season four of Star Trek: Deep Space Nine.
In the previous episode, “The Way of the Warrior: Part 1”, the Klingon Empire was attacking Cardassia after the military government was replaced by a civilian one thanks, in part, to the destruction of the Obsidian Order in “The Die is Cast”. The Klingons believed that the civilian government was actually Changelings.
The Federation had refused to help, and in return Gowron had cancelled the peace treaty between the Federation and the Klingon Empire, the Khitomer Accords, that had been signed in Star Trek VI: The Undiscovered Country. Gowron has also invited Worf to join him in the attack on Cardassia.
Worf refuses, and Gowron doesn’t take it that well. When Sisko hears that the Klingons are advancing on Cardassia Prime, he contacts Dukat and offers to help evacuate the civilian leaders in the Defiant.
This action leads to a battle, both space and hand-to-hand, as the Klingons attack DS9. The station, however, has been having upgrades installed.
Space battles were never very common in The Next Generation, where talking things out was far more common, but DS9 sees a lot more of them.