Deep in the Atlantic, beyond the Strait of Gibraltar, an expedition discovers something that should not exist.
A structure buried for thousands of years.
A signal with no possible source.
And data someone is already trying to erase.
Then a woman is murdered.
Aren Voss, a former intelligence officer turned aerospace accident investigator, is brought in to find out what happened. Leena Sarin, an expert in precision timekeeping, holds another piece of the puzzle-one that defies explanation.
Together, they begin following the trail the victim left behind.
But someone is always one step ahead.
Records are altered.
Evidence vanishes.
And every time Aren and Leena get closer to the truth, they uncover something older, larger, and far more dangerous than either of them imagined.
Whatever was found beneath the Atlantic did not stay buried.
And soon, Aren and Leena won't be the only ones trying to reach it.
With sabotage closing in, enemies on their trail, and no way to undo the choices ahead of them, they must discover what they've uncovered before someone else learns how to use it.
Some doors were never meant to be opened.
This one just was.