Dr. Smith's carelessness causes a vital power unit to overload and the Professor orders a power ration until the system can be repaired; this means not recharging the Robot who is critically low on power. The depressed Robot uses his remaining power to go off and die alone, but Will refuses to let him go and he and Smith track him down into a dangerous area of unstable atmosphere. There, the two are shocked when they find the bizarre gases of the area have caused the Robot to grow to the size of a house. Will and Smith then venture inside the massive robot in hopes of stabilizing his power systems and returning him to normal size.