Kashyyyk is the home of the Wookiees. It is a lush forest planet. Imperial Spies locate a Jedi in hiding, so Lord Vader launches a massive imperial invasion on Kashyyyk. The Jedi hiding was a man named Kento Marek, who was Galen Marek's father. Before Vader fought Kento, he destroyed Wookiees and saw his Stormtroopers fighting them too. So then Vader fought Kento Marek and defeated him. He choked him and left him there. He then saw his son named Galen Marek with a Lightsaber. Vader took the Lightsaber from him and took young Galen Marek with him for training for being his apprentice.
After the first battle and takeover of Kashyyyk, a skyhook was built that transported captured wookies to the Death Star. Ozzik Sturn was the overseer of the skyhook. Princess Leia is stuck in a building. You have to go to the planet to save her and wookie prisoners. After you free her, she requests you free the rest of the wookies, and destroy the skyhook. In the process you kill Ozzik Sturn.