Unlocking this level requires a minimum of 40 Gold Bricks and is located in Kerroc. The walkthrough writers give a good description on completing the level:
Head right and use Quiggold to blast the gold bricks blocking the way. Have Sidon Ithano pull down the yellow droid thing next to the blue flame. Multi-build up and use Quiggold to pull on the orange handles. Deal with the troopers and smash the glowing box on the right inside the room. Build it into orange handles and pull them. Switch to Pru Sweevant and throw a thermal at the silver machinery revealed. Head back out, smash the multi-build and rebuild it right to put out the blue flame. Deal with the troopers, head up the stairs and deal with some more, then head out over the bridge.
Head all the way right until you come to a gap in the walkway. Throw a thermal onto the pipes on the back wall to bring out a floating droid with a grapple and grapple up to the left as Sidon. Head into the foreground and then turn right and grapple across with another floating droid. Use the boost pad to hop across the gap and then drop down and deal with the troopers. Smash up the glowing box to the right and then multi-build left to make a bunch of hop-platforms for the other two characters. Use Quiggold to pull the orange handles to the right.
Deal with all the troopers around the corner and then smash up the debris at the back of the corridor to reveal a small grate which Pru can get through. Chuck a thermal at the silver object directly behind you when you get out of the grate. Hop back down and head across the bridge you have created. You'll need to defeat 12 Stormtroopers on the far side, and then use Quiggold to take out the gold-plated TIE fighter hovering above. Switch to Pru and chuck a Thermal at the next TIE fighter when it appears, which will be silver-plated. Sidon will be able to double-jump up the crashed platform and deal with the Stormtrooper up top. Head right and grapple across and then smash up the glowing object. Rebuild it into an elevator to bring the two characters up. A scan area appears - scan it with Sidon and point at the middle of the machine directly behind you. Use Pru's thermals to blow up the mechanism in the middle. Hop down as Sidon and scan the right pillar with a wheel shape on its side. Have Quiggold shoot away the revealed gold section, and then Pru can throw a thermal at the object behind it. Build up the debris into orange handles on the left pillar which Quiggold can pull. Pru can then throw a thermal at yet another silver object behind it. Head inside to finish the level.
Here is a video walkthrough of the level:
Credit to HappyThumbsGaming.