The Decrypter and the Beale Ciphers

Two hundred years ago, a man hid a fortune and left behind three encrypted letters. No one has cracked them. Until now.

When Calla Cress and her closest friend Jack Kleve uncover ancient wall paintings and a hidden telescope deep inside a New Mexico cave, they realise the Beale Ciphers don't lead to gold. They lead to something far more dangerous.

Then the cave collapses. Jack vanishes. And Calla is named the prime suspect in his disappearance.

Forced to run, hunted by her own government, Calla follows Jack's final clues across continents — through the Chihuahua Desert, the souks of North Africa, and the Atlantic coast, decoding a centuries-old secret guarded by people who will kill to keep it buried. This is not a treasure hunt. It is a race to prevent something that could reshape civilisation.

"Emotionally charged and relentlessly paced — Sandy is at the top of her game."