It transpires that Sister Agnieszka is an agent whose intent was to kidnap and sell Jinny.

Adding a subplot involving slave traders.Dr Gerard, a Frenchman in the novel, becomes Scottish, develops a witty personality and becomes an accomplice to the murderer (whereas in the novel, he is completely innocent). Lady Westholme, a U.S.-born Member of Parliament, becomes the unconventional British travel writer Dame Celia Westholme in the adaptation. Jinny (Ginevra, in the novel) is adopted like Raymond and Carol, and she also becomes the prime motivation for the murderer, whereas in the novel she was Mrs Boynton's sole biological child. In the adaptation, Jefferson Cope was one of the orphans severely abused by Lady Boynton in his youth, and he decides to take his revenge by wiping out her financial empire and ensuring that she is kept in the dark, though she dies before she realizes her financial ruin.

Altering the backstories of several supporting characters.

She couldn't have any children of her own, so she selected her children from orphanages, all of whom were badly abused and tormented. In the adaptation, she is also a sadist, albeit one who has compiled a financial empire. In the novel, Mrs Boynton is a tyrannical sadist whose occupation had been a prison warden, which is central to her murder.

Omitting characters such as Nadine Boynton and Amabel Pierce.

Adding new characters that never appeared in the original novel, such as Lord Boynton, Nanny Taylor, and Sister Agnieszka.

Moving the central setting of the story from Petra in southern Jordan to an archaeological dig Ain Musa in Syria, where Lord Boynton is searching for the head of John the Baptist.

At the same time, Mrs Boyton's sadistic behaviour provides a number of lies and deceptions that make it fun to follow Poirot's investigations and keep guessing the resolution to this mystery. There is something compelling about the vile Mrs Boynton as none of the people around her find the strength to tear away from her even though this would ultimately be for their own good.

Christie focuses once again on the relationships between the characters and uses psychology to map out what makes those relationship keep intact. Poirot, having once overheard a conversation between two of the Boyton children, is resolved to investigate when a death occurs on a trip to Petra. Boynton one of the most despicable characters and one of the most deserving victims in any Christie novel. All of her children live under her thumb and it is easy to see how her manipulative tyranny make Mrs. Boynton is despised by everyone who meets her. 'You do see, don't you, that she's got to be killed?'

Christie appointment with death