ABC Conjecture?

On an uninhabited desert.

Two rovers driving from a distance merged together.

Han Kangyu opened the car door and jumped out. He looked at Sun Wenzhe approaching him. Han Kangyu was wearing a spacesuit. He strode forward and asked with an anxious expression on his face, "Did you find him?"

With a solemn expression in his eyes, Sun Wenzhe shook his head.

"Nope. I've searched everywhere nearby. I can't even find the crack where he fell… What about you? Did you find any clues?"

After hearing the bad news, Han Kangyu had an ugly look on his face.

"Nothing on my side either."

He searched almost every corner he could find; he even ventured a short distance toward the inside of The Gates of Hell mountains. However, the result was just like what his teammate Sun Wenzhe said, he couldn't even find a crack in the ground, let alone a person.