When it first happened it seemed like something from a particularly trashy airport novel (or an Umberto Eco novel, depending how you looked at it): a London postman on his way to work comes across the body of a Italian banker hanging by the neck from the scaffolding under Blackfriars Bridge.
And then it got worse...
Turns out Roberto Calvi (a devout Catholic) was actually an ex-banker because he'd left his job as chairman of Banco Ambrosiano the day before. His secretary had committed suicide and the bank was about to go under due to £800m worth of debts.
And did we mention that some of those debts were owed to some less than salubrious organisations like the Sicilian Mafia and (worse?) the Vatican?
The original verdict of suicide was met by derision by 'those in the know', and a second inquest came up with no conclusions. But Calvi's son hired private detectives to carry out forensic tests that the City of London police hadn't and they seemed to prove Calvi couldn't have killed himself. So in 2003 the case was reopened.
Today, almost a quarter of a century after his body was found, five people will go on trial in Rome accused of killing Mr Calvi.
The five people are two Italian gangsters who were in London at the time, two men who accompanied Calvi on his trip from Rome to London, plus a girlfriend of one of the men.
We already know some of the details: Calvi's trip to London from Italy for example, which involved a private flight to Venice in the dead of night, a quick trip by speedboat to an abandoned pier in Yugoslavia, a chalet in Austria, and a false identity as a Fiat executive for his arrival in London where he holed up at a £40 night hotel in Chelsea. A room he didn't leave until the night he died.
But it's likely that the trial will uncover even more twists and turns in a story that doesn't seem to want to go away. Question is: if they prosecute the workmen will they leave it there or will they then go after the men who pulled the strings?
...And how exactly do the Freemasons fit into all this?