A stone at the end of the exit was pushed by the tip of a shoe.
With a plop, it fell into the ever-flowing underground river, making no significant ripple with the water it displaced.
Casio looked to the left and right, it was a rock layer tunnel eroded by the underground river, with a diameter of more than ten meters.
The river rushed from left to right, flowing fervently.
"According to the map, this is a river that runs through the bottom three layers of the ruins. We can reach the fourth layer by following its flow," commented Sheng Feinan after a glance at the map.
"No, skip the fourth layer and go directly to the fifth one," replied Casio, his eyes flashing.
"Straight to the fifth layer? But, the map indicates that where the underground river meets the fifth layer is the most dangerous area."
Sheng Feinan slightly furrowed his brows.
