As the light source released by the fluorescent rod was absorbed by the strange flying machine, the cave became dark again. There was only one fluorescent rod left in Zero's hand. He did not even dare to approach the metal wings of the airship, afraid that he would even absorb the remaining light.

This unknown civilization seemed to be very advanced in the use of light. However, the weak light emitted by the fluorescent rod could also become the energy of the metal wings, which ...