After the droid-centered hijinks of the last two episodes, Star Wars: The Clone Wars returns to its core competencies this week, with clone troopers riding AT-RTs into battle against overwhelming odds and a mysterious enemy. This time, the brutalist tactics of Jedi general Pong Krell make it even harder for the clones, as they try to take the capital of Umbara.
This week's episode, "Darkness on Umbara," is the beginning of a four-part story arc that details the attack and its consequences. Here's a clip: