Geonosis has mostly fallen under Republic control, but Archduke Poggle the Lesser has evaded capture. Jedi Master Luminara Unduli is on his trail through a massive sandstorm that has grounded Republic ships and interfered with communications. Luminara and the Clone Trooper accompanying her track Poggle and his Battle Droids to the Progate Temple, which the Republic had thought cleared earlier. While searching the building, a Clone Trooper inspects a hole leading to the underground tunnels. Luminara calls in to inform Obi-Wan and Ki-Adi-Mundi that Poggle appears to have entered the catacombs underneath the temple, where a scream is heard and the transmission cuts out.
The sandstorm has ended. Anakin Skywalker, Obi-Wan Kenobi, and Commander Cody have arrived at the Progate Temple in search. They find the body of the Clone Trooper accompanying Luminara, as well as her lightsaber, and it's concluded that Luminara must have been taken below ground. The search party forms up and enters the tunnels.
The tunnels seem to stretch on forever and there's no sign of Master Unduli — until Anakin and Obi-Wan get a brief message from her that told them to leave before she's taken down by some odd-looking Geonosians. Anakin and Obi-Wan decide to continue on, reasoning Luminara can't be far away. They are shortly attacked by a group of the odd-looking Geonosians, who they discover to be undead, kept mobile through some kind of parasitic control. They are extremely difficult to kill and the search party eventually finds itself on the run. The Jedi decide they need reinforcements and two Clone Troopers are sent to report back because they're so deep that their comm signals can't make it to the surface. They don't make it because they're attacked by the zombie Geonosians.
They eventually find their way to where Luminara is being held — the chamber of the Geonosian queen Karina the Great, whose existence was previously only rumoured. Karina wants to see if one of her brain worms can control a Jedi Master. The Clone Troopers position themselves around the edges of the room for an ambush and the Jedi walk straight in.
The ambush is sprung, Luminara is rescued, Poggle is arrested, and Karina is killed when the pillars supporting the ceiling of her chamber are shot out, causing it to collapse.
- Badass in Distress: Luminara gets captured by the undead Geonosians at the Progate Temple and makes an escape attempt before she's rescued.
- Blinded by the Light: The ambush plan involves the Clone Troopers using the lights mounted on their helmets as Karina and the zombie Geonosians spend all their time in the dark.
- The Cameo: Ahsoka, Barriss, and Rex appear at the beginning of the episode. The former two say goodbye to the latter.
- Deadly Dust Storm: The sandstorm at the beginning grounds the Republic gunships and screws up communications, so help can't come immediately when Luminara goes missing.
- Glowing Eyes of Doom: The zombie Geonosians have glowing white eyes.
- Hive Queen: Karina can control her subjects through the brain worms.
- Nightmare Fetishist: Obi-Wan is way too curious about seeing if a brain worm actually could control Luminara. Anakin and Luminara call him on it. However, it turns out he was trying to get the guards to turn their attention away from him and Anakin so they could break free and rescue Luminara.
- Night-Vision Goggles: Yet again, we see the night vision feature on the Clone Troopers' helmets being used, prior to the ambush.
- Not Using the "Z" Word: Averted. The undead Geonosians are explicitly called "zombies".
- Our Zombies Are Different: Insectoid Aliens controlled by parasitic worms? That's a new one.
- Puppeteer Parasite: The Geonosian brain worms are linked to a Hive Mind and controlled by the queen. They can even control Geonosian warriors after death.
- With My Hands Tied: Luminara, while handcuffed, puts up a good fight against the undead Geonosians while attempting to escape.