A sunken Soviet submarine packed with nukes. A window for America to gain the upper hand in the Cold War. A CIA cover story worth three billion dollars. I give you Project Azorian, or how the U.S. tried to steal a Soviet sub.

It’s the late 1960s.

Nuclear submarines are a key cog in a country’s deterrence capability. ICBM silos could be located or betrayed. But a sub slithering through the cold oceans ensures that no strike would ever go unavenged.

March 1968 — North Pacific Ocean.

The Soviet Pacific Fleet scrambles into action. K-129, a patrolling Golf II nuclear submarine, carrying three nuclear ballistic missiles and two nuclear torpedoes has just sunk, some 2,000 miles northwest of Hawaii.

The fate of her crew, but more importantly of her classified arsenal, cryptographic devices, and codebooks, is on the balance. The Russians go all in. Nothing. Despite a vast search-and-rescue operation, two months pass with no results.

The unfortunate K-129. She went down with all hands after an internal explosion (CIA.gov).

The task force retreats to its base.

A prying CIA senses an opportunity. Surely, they argue, the Soviets have just lost a nuke sub. Nothing else would explain such an uncommon activity. Interestingly, a network of hydrophone listening stations, called Sound Surveillance System (SOSUS), traversed (and still does) the American coasts, ever vigilant for any unnatural noise that could result in an intelligence coup.