He was portrayed by the late Philip O'Flynn.
Throughout his life, Broughton had managed to accrue a large sum of wealth. After relentless poor treatment from his family and many years of the Broughtons' sponging off of him, Gabriel faked his death. His family are notified by solicitor Everett Sloane to gather at Blackshaw Towers to attend the reading of his will.
Gabriel had made sure that not a single one of his relatives would inherit any of his money, the only one with any form of inheritance is his nurse, Linda Dixon, who is bequeathed his medicines and syringes. A power cut occurs, during which Gabriel kills Dr. Edward Broughton, his brother. The case is declared a homicide by posing-solicitor Syd Butler, a bookmaker. Butler attempts to make a call to the police but discovers the line has been cut mysteriously. Butler and Sloane instruct everyone to keep themselves locked in their rooms.
Struggling to sleep, Gabriel's nephew, Ernest, finds himself in the parlour room where he begins to (poorly) play Chopsticks on the organ. Ernest's indistinct relative Malcolm, a pianist, approaches the organ and takes over from Ernest. While the two are playing happily, Gabriel enters and stabs Malcolm, causing him to collapse onto the organ. Gabriel manages to leave the room before Ernest had noticed Malcolm had been stabbed and locks it from the inside. Sloane begins to (wrongfully) accuse Ernest of having murdered Malcolm.
After Syd and Ernest prove their innocence having found a secret passage in the parlour room, indicating the killer escaped and locked the door on the inside, the survivors decide to assemble in the lounge. Beginning to panic, Janet, Gabriel's niece, starts rambling and accusing anyone possible. Hearing this from behind a painting, Gabriel shoots a posioned blowdart at Janet, killing her.
The survivors begin to blame Fisk, the butler, as he was the only one not present in the room after Janet was posioned. However, on discovering Fisk, it is apparent he has not moved for several minutes due to the untouched ash on his cigarette.
On returning to the lounge, the senile Aunt Emily insists she had spoken to Gabriel while the remaining survivors left her to knit in the lounge. The group discredits this due to her age and weakening mind. Guy, Gabriel's nephew, is then indicted for the murder until his body is discovered in the cocktail cabinet. Sloane decides he will venture into the village to alert the police.
At last, an Inspector Arkwright arrives following Sloane's request. On hearing the tenuous details of the crime, Inspector Arkwright begins to cast doubt on the validity of the report as each of the bodies have disappeared. Arkwright requests to see the coffin of Gabriel after Syd suggests it is Gabriel who is committing the murders. Arkwright and Syd discover the coffin has gone missing. Arkwright returns to the lounge while Syd and Ernest reconvene in the courtyard, where they discover Sloane's body perched on a fountain. Syd and Ernest discover that Arkwright is not an inspector at all. Arkwright captures Syd and Ernest and takes them into the basement where Aunt Emily and Linda are held. Arkwright reveals himself to the remaining four survivors as Gabriel and explains his motive. Gabriel then reveals a pack of dogs that "have not been fed for ten days" will be the fate of the survivors as he escapes.
Stoking the fire in the lounge, Fisk finds Gabriel attempting to flee from the tower. Gabriel turns his pistol on Fisk, who throws a burning log at Gabriel, disorienting him, causing him to fire a shot which results in a chandelier falling on him. Fisk goes down to the basement where it is revealed the dogs are of no danger at all as Fisk had been feeding them having noticed Gabriel neglecting them.
Broughton is an eccentric man, but appears to be in denial of this and takes offence to this comment easily. He is stingy and perhaps narcisistic too in that he believes very much in his own genius.