One of the most audacious acts of sabotage in modern history, the operation worsened an energy crisis in Europe—an assault on critical infrastructure that could be considered an act of war under international law. Theories swirled about who was responsible. Was it the CIA? Could Putin himself have set the plan in motion?

Now, for the first time, the outlines of the real story can be told. The Ukrainian operation cost around $300,000, according to people who participated in it. It involved a small rented yacht with a six-member crew, including trained civilian divers. One was a woman, whose presence helped create the illusion they were a group of friends on a pleasure cruise. 

“I always laugh when I read media speculation about some huge operation involving secret services, submarines, drones and satellites,” one officer who was involved in the plot said. “The whole thing was born out of a night of heavy boozing and the iron determination of a handful of people who had the guts to risk their lives for their country.”