The Recurrence Protocol

Every eighty-seven atomic clocks on Earth agreed for seven seconds.

That is supposed to be impossible.

NASA astronomer Daniel Mercer finds the anomaly at 2 a.m. on a quiet Tuesday, buried inside a secondary model he was not supposed to be running. By morning, a classified program that has been monitoring the same signal since 1945 knows he has seen it. Within a week, he knows why they have worked so hard to keep it buried.

The signal traces to a twelve-thousand-year-old monument in southeastern Turkey. Göbekli Tepe is older than agriculture. Older than the wheel. Older than anything the historical record is supposed to allow. And the builders carved their message in stone, encoded three ways, so that it would survive long enough to be read when the instruments finally caught up.

Not a warning. An instruction.

Daniel has eighty-three days to decode what is coming. Archaeologist Miriam Hale, working the Karahantepe dig in Şanlıurfa, has the second piece. A Swiss institutional archive has the third. The people running it have already decided the world is not ready