One Down - S1.E13

The Defenders find the way to the pure stone, and eventually find themselves in a maze. Mel sees the pure stone and picks it up, only to have it practically take over her body! But when the others find her, the Dakonauts (Lord Nazmul's unstoppable robotic army) attack them! Erik and Kara take Mel to safety, while Seth distracts them using the pure stone. Later, Kara gets a sigil spirit from zad that shows her what Mel is thinking, and when the first stone is finally acquired, it is at a terrible cost. Now the goal is not just to get the rest of the stones, but to save Mel's life.