Twelve-year-old Don Boyd, smart in his Loretto Junior School uniform of blue serge shorts, open-necked shirt and long red stockings, was about to undergo a particularly "special", secret lesson as he crept towards North Esk Lodge.
This would be a private lesson, the first of many. Just the young boy and his charismatic, popular and - although the schoolboy didn't realise it at the time - predatory, paedophile French teacher.
It was a lesson in life that pioneering 19th century headmaster Dr Hely Hutchinson Almond - whose "mind, body and spirit" values are at the heart of a school that counts Alistair Darling, Andrew Marr, Norman Lamont and racing driver Jim Clark among its past pupils - surely would never have tolerated.
Inside North Esk Lodge was Guy Anthony Ray-Hills' bedroom.
It smelled of gelatine cream, aftershave and semen. It reeked of sex and secrets, of terrible child abuse and broken childhoods.
Within this small bedroom on the top floor of North Esk Lodge, a ten-minute walk from the gates of prim Loretto School at the heart of Musselburgh in the late 50s and early 60s, curious, innocent boys - often deprived of parental affection at a lonely boarding school - were treated to Ray-Hills' full and undivided attention. They were stripped, abused and repeatedly raped.
Boyd kept secret how he became one of the outwardly respectable French tutor's "special friends" for decades. It tainted his life and relationships and hovered quietly in the background as his career in filmmaking led to working with stars like Sir Laurence Olivier, John Hurt, Richard Harris and Dame Helen Mirren, producing iconic movies such as controversial 70s film Scum, writing screenplays and directing.
He blurted his secret out, bizarrely, in an explosive moment after his father's death, when a friend showed off a collection of antique guns, fired one and the blast somehow broke the lock on decades of suppressed anguish.
Today he's back in Edinburgh, just a few miles from where Ray-Hills systematically abused him, to work with the Traverse Theatre and launch a new project which aims to beam live theatre to cinema audiences across the country.
It's also an appropriate location to launch his first novel, Margot's Secrets, with its themes of sexual abuse and mind manipulation, deep- rooted secrets and lives warped by depravity which run brutally close to Boyd's own experiences. So close, that one of his key character's own account of being brutalised by his teacher - even down to the animal nicknames Ray-Hills gave his pupils and the school uniform - could not be anything other than Boyd's own story.
"One of the victims is drawn from my own experience," nods Boyd during a break at a rehearsal room in Leith. "And yes, one of the other characters is the personification of what I imagine my former teacher might become as they enter the adult world away from boarding school.
"He is charming and dangerous. Intelligent, perceptive and a very, very clever manipulator of people."
Here in Edinburgh, so close to that small bedroom, Boyd might be expected to harvest fresh bitterness and anger at his betrayal. "But I'm one of the lucky ones," he stresses. "I can come back to Edinburgh which I feel is my 'home' and be completely forgiving to Loretto. It was a brilliant school educationally, there was the highest order of teaching staff and it gave me the opportunity to learn so much.
"One has to move on. You have to rationalise, otherwise you go around with a scar that never heals, a constant reminder of something that happened a long time ago."
He agrees that ultimately Loretto failed him - and other boys abused by Ray-Hills during the 16 years he taught at the Musselburgh school. But he insists it also introduced him to theatre and cinema, music at the Usher Hall and Shakespeare, laying down credentials for what would become a hugely successful movie career.
His 70s production company, Boyd's Co, was at the forefront of British cinema for a decade, bringing to the screen Alan Clarke's groundbreaking and controversial movie Scum - infamous for its brutality and sex abuse scenes - Derek Jarman's The Tempest, Sex Pistols movie The Great Rock 'n' Roll Swindle and Lindsay Anderson's Look Back in Anger.
Boyd has worked with a string of British talent, from Ray Winstone to Stephen Fry, Kathy Burke and Tilda Swinton. In 1988, he worked with Jarman again (pictured below) on War Requiem, Laurence Olivier's final film.
Yet while his career flourished - he's been described as a "one-man film industry" - Boyd's private life and marriage was in turmoil. Events at Loretto between 1958 and 1965 lurked in the background, repressed but the catalyst for his own adulterous and duplicitous adult behaviour.
Boyd was born in Nairn and was ten when he was sent to Loretto while his parents lived in Africa. "School was horrendously brutal but I thought that was normal and life was like that," he recalls.
The abuse began after months of careful, cynical grooming by his tutor when he was 12. It continued throughout his year as head boy at the prep school and into senior school. As he prepared to leave Loretto as a teenager, Ray-Hills accompanied Boyd on holiday to Austria where the abuse continued. "I was ashamed and couldn't cope," Boyd recalls. "Then came hiding it. The impact on your life that hiding something like that has is huge. It caused a lot of turmoil and crises."
When he finally revealed his secret in 2001, Loretto acted immediately, contacting everyone who'd ever been taught by Ray-Hills. "There were 35 letters back from people saying similar stuff had happened to them," says Boyd. One man claimed the abuse had driven him to attempt suicide.
Ray-Hills, then in his late 70s, was charged with a string of sex offences but the case was dropped on grounds of his ill-health. The shame of being "outed" for years of abuse would, Boyd believes, have been enough of a punishment, jail a given if he had stood trial.
Ray-Hills is now dead. "Nothing was ever done to him while he was a teacher," Boyd recalls. "He left Loretto and it was brushed under the carpet in a way that must have been done by lots of organisations at the time - the Catholic Church, public schools. But I don't really hold Loretto to blame."
Today it's in Boyd's past, but curiously events from 50 years ago could also feature in his future too.
His X-rated psychological thriller, Margot's Secrets - based around an American psychotherapist in Barcelona's ex-pat community where everyone has a sexual history they'd rather keep hidden - is already the subject of discussions between his publishers and American film producers as potential movie material.
Although he insists it is fiction and not memoirs, drawing on elements of his own story and unravelling tracts of Ray-Hills' make-up for his characters has been a cathartic experience, Boyd adds.
"I suppose integrating Ray-Hills in a book as a character has been my way of laying the ghost to rest."