Captured by the Deep Sea: Infinite Vehicle Evolution

[Deep-Sea Survival] [Infinite Flow] [Lone-Wolf Heroine] [Vehicle Upgrades] [Bizarre Ideas] [Overwhelming Deep-Sea Environment + Solo Submarine Upgrades + Extreme Bizarre Ideas]

After waking from a deep sleep, all of humanity is swept into the cosmic-scale selection experiment known as the Cycle Vast Sea. Everyone starts with one randomly assigned vehicle and must face deadly, bizarre abysses such as jelly seas, inverted seas, and liquid-metal seas!

An ordinary city girl is dragged into the deep sea and starts with the weakest vehicle: the Firefly, a tiny one-person research submarine. No teams, no companions, just endless deep-sea mutations and terrifying environments!

While everyone else is still desperately struggling in ordinary waters, she has already followed the perfect upgrade plan of