The USS Yorktown encounters the Super Star Destroyer Executor

Captain Giotto took the USS Yorktown near the Klingon border when it encountered a vortex. Emerging from the vortex was the Super Star Destroyer Executor. The Klingons attacked the Executor with 3 D7-class battle cruisers and she destroyed all 3 but suffered bad damage. Captain Giotto reported the incident to Starfleet, which sent the entire Federation First Fleet to intercept her. A fierce battle ensued in which 6 Federation starships were destroyed and another 10 suffered bad damage. The Executor was not so lucky. She was destroyed with all hands lost, except for Darth Vader, who escaped in his TIE Advanced Fighter. Vader went through the vortex and went back to his universe. He then went back to Coruscant, where he met up with his Master, Emperor Palpatine.