Uncontacted (en Inglés) - Sam CJ

A routine camping trip ends when a luxury overland camping vehicle crashes through the ground of the Siberian taiga into a cave system no one knew existed. The sole survivor stumbles out of the wilderness days later, delirious, with photographs of something that shouldn't be there.

Dr. Vera Krestova is a paleoanthropologist. She studies the dead. When one of the wealthiest people on the planet funds an expedition to investigate the survivor's story, Vera is recruited for reasons she doesn't fully understand. She knows that science funded by billionaires comes with conditions. She doesn't yet know how far those conditions will go.

Half a million Euros for a few weeks chasing fever dreams. Easy money.

Nobody expected to find anything. Nobody was prepared for what they did.

What they uncover will rewrite the history of our species. What they aren't allowed to tell could rewrite everything else.

Humankind's first contact with two alien intelligences. No aliens required.

For readers of Kim Stanley Robinson, Peter Watts, and the early James Rollins.