Who could have guessed that what lay outside was merely an ordinary little hill, while inside it contained an entirely different world? No— even that was too modest a description, because there was actually another world beneath it.
Following the terrain downward, they did not feel the surroundings growing darker and more mysterious. Instead, everything grew brighter, and the environment improved by the minute. Especially after they passed through a massive tunnel resembling a subway passage, the scene before them almost made Zhang Yang and the fat man Du Wei feel as though they had crossed over into Earth's civilized society—if only the streets had not been packed with ugly Frog People.
Zhang Yang and Du Wei were both dazzled, their horizons blown wide open. The Frog People's technology had already developed railways and aircraft, and seemed to be slightly more advanced than Earth's.
"Two outsiders, please register here."
A Frog Person in a gaudy coat came over and spoke very politely. What was more, it spoke fluent Earth language. Zhang Yang and Du Wei were no longer surprised by such things, especially when the other party produced a thick stack of documents titled Relevant Agreements Between the Diwa Two Races Regarding Personnel Exchanges and Diplomatic Affairs, and Methods for Handling Several Emergencies.
After finishing the registration, each of them received a thick book of precautions, and Zhang Yang and Du Wei entered the Frog People's city. At that moment, Du Wei suddenly spoke thoughtfully. "Do you remember those two Gravity Grenades of mine? The material used inside them might have come from here."
"What material?" Zhang Yang asked curiously. The Gravity Grenades were not especially powerful, but the gravitational fields they created were quite impressive.
Du Wei did not answer. He merely continued, "I was originally just a mechanical