The episode opened with Jo finishing her test for the Astraeus mission while Carter was wrangled into replacing her at GD by Senator Wen. Jo, Fargo, Holly, Zane, and Parrish are tricked into meeting in a lower level of GD for the next stage of testing for the mission.
Meanwhile Allison really wanted to go back to work but Senator Wen did not feel she was ready. Carter starts to find things made if Tungsten missing including an elevator and the support beams of the floor in a lab.
It turns out that some builder mites that one of the Scientists used to build the Astraeus hull had not stopped when they were done and were consuming Tungsten and building hull pieces. Unfortunately as the mites ate their way to the strongest source of Tungsten it put the 4 candidates in trouble as they were sitting inside if of it.
Allison, Carter, Wen and Dr. Fong came up with the plan to use sonic waves to stop the mites and Allison lead Carte through the maze of Level Q to the chamber where the 5 candidates were trapped and released the sonic “bug bomb” and stopped the mites before anyone was really hurt.