Turning the tide! As Separatist control over vital but isolated supply routes expands, Republic forces invade a key planet -- the darkened world of Umbara.

In the midst of helping Obi-Wan Kenobi's battalion conquer the Umbaran capital, Anakin Skywalker is called away to Coruscant. His battalion is temporarily placed under the command of Jedi General Pong Krell -- a shrewd and temperamental leader. Krell's reckless strategy forced Captain Rex to retreat with his platoons in a disastrous defeat.

The 501st troopers hold their ground against a withering assault by Umbaran forces. Obi-Wan's troops are unable to take the capital because the Umbarans are being resupplied and bolstered from a nearby airbase. It is up to General Krell and the 501st to neutralize the airbase. The entire mission is counting on it.

From a steep ridge, Clone Captain Rex and Krell spot the distant airbase shining like a beacon. Krell orders a bold direct assault, though Rex disagrees with the general's strategy. The terrain will channel the 501st into a single gorge, making them easy targets. Krell will not be swayed from his plan: there is no time to explore the land for alternatives.

Rex breaks the news to his troops that they'll be splitting into two divisions and marching directly into the enemy. Many of the veteran troops -- Kix, Jesse, and Fives for example -- complain about Krell's tactics. Younger clones like Dogma are much more accepting of their orders. Hardcase just wants some action. Rex reminds the soldiers that their duty is to follow orders, even if it means laying down their lives.

As the 501st march into the gorge, the ground suddenly erupts as a mechanical monstrosity rises to the surface. The multi-segmented worm-like vehicle is an Umbaran crawler tank, heavily armored, lined with laser cannons, and capable of wildly thrashing its segmented body with bone-crushing strength. The howling machine shrugs off all incoming blaster fire as it charges towards the clones.

Clone troopers scramble to get a rocket launcher into place. Hardcase fires a missile directly at the crawler tank's head, shattering the cockpit in a fiery blast. A chain reaction blows apart the serpentine armored vehicle. Rex orders his troops to regroup as four more crawler tanks continue the rampage.

Rex has his troops line the ground with detonators, and then lure the crawler tanks into the booby-trapped passage. Rex triggers the explosives. The trapped tanks are destroyed in a tremendous blast that lifts Rex into the air. The crawler tank threat is neutralized.

The respite is short. As the clones march through the seared wreckage of the tanks, the ground once again shudders. Rex peers through his electrobinoculars to spot an even bigger threat. Several ponderous Umbaran MHC juggernauts push their way through the vegetation. These immense walkers scorch the underbrush with their immense cannons, sending clones flying everywhere.

Back at the entrance to the gorge, General Krell watches the fight through his electrobinoculars. He impatiently urges Rex to stand his ground. The rest of the battalion is depending on their success. Though Sergeant Appo, standing at Krell's side, offers to move in reinforcement platoons, Krell does not give that order.

Rocket launchers prove ineffective against the MHC tanks. Rex has run out of options, but he must continue the assault. Other troops like Kix, Jesse and Fives are stunned by Krell's commands. Kix even starts to resent Rex's orders. The 501st take cover in the vegetation, trying to avoid the devastating enemy firepower. Rex then gets an idea.

Rex's plan is to send Fives and Hardcase ahead to the airbase, where they are to stealthily commandeer some Umbaran starfighters for some much needed air support. When Rex explains his tactics to Krell, the Jedi general is furious. He cannot believe Rex would entrust so vital an operation to two clones. He orders Rex to immediately continue his frontal assault.

Fives and Hardcase use the surrounding vegetation to sneak over the fence guarding the airbase. They narrowly avoid making too much noise and drawing attention to themselves when a curious banshee flutters past them, but Hardcase is able to silence the beast not with a blaster shot, but by spearing it with his ascension hook.

Fives and Hardcase find two unattended Umbaran starfighters and activate their high-tech touch-sensitive cockpits. The anti-gravity vessels spin around, barely under control, as the clones steal them from the airbase.

Fives and Hardcase are able to bring the fighters under enough control that they pilot them into the gorge and blast the MHCs. With the heavy artillery eliminated the clones are able to press forward and capture the airbase. Even Krell is impressed by this fortunate victory.