SPOILERS: Do not read if you have not read or watched the movie and don't want to know the ending

I got this book on Christmas and just finished it, wanted to read the novel before I saw the movie. I thought it was actually very good and I loved the ending as well as the truth about the murder. I somehow figured out the gist of what was going on while reading Part 2 of the book just by looking at everything from the bigger picture:

• At the time of year that the story takes place most trains were almost completely empty, but this passage of the Orient Express was booked up.

• Mary Debenham was very anxious to get on that exact train, not just the Orient Express in general but the one that took off from the Tokatlian Hotel at 9pm.

• Not only was the train packed, but it consisted of some extremely high-profile people. It would be rare to be on a train with a Russian princess alone, but to also be on that same boarding with a Count, Countess, English Colonel, etc. etc.

It became very obvious that they were all there in the same coach for a reason, the murder of Cassetti. I thought it was all very well written, and the ending is probably the most satisfying ending that could have happened, but there are still some things that don't make sense to me.

Throughout the first half of the story, I thought that M. Bouc and Dr. Constantine were the most suspicious people on the train. They presumed to be investigators even though they were also there when the murder happened. Eventually I threw that idea out of my head as I saw that the story was heading in a different direction, but the story doesn't exactly explain why M. Bouc or Dr. Constantine are even there, or why Poirot is there in general.

Lets back up for a sec. After taking the Taurus Express at the beginning of the novel, Poirot ends up at the Tokatlian Hotel and isn't planning on getting on the Orient until the next day. However, he receives a letter from his employer telling him to get on the next train possible (where he ends up being the only person in the coach who isn't a conspiring murderer). After he decides to take the 9PM train, he runs into an acquaintance who is somehow going to be on that same train. That acquaintance somehow ends up being the director of the Compagnie Internationale des Wagons-Lits, the company that is the operator of the Orient Express. Later on when the Orient stops at Belgrade, Poirot's bags are moved to M. Bouc's compartment and M. Bouc's luggage is moved into another coach with the newly boarded Dr. Constantine. Earlier, when Poirot is talking to MacQueen it's revealed that Poirot knew that his bags were going to be moved while at Belgrade. It's possible to assume then, that Poirot knew Dr. Constantine was coming aboard and that M. Bouc was going to be boarding with him. There wasn't a conversation in the novel where M. Bouc and Poirot talked about changing cabins at Belgrade, but Poirot still knew about it before it happened.

All of this makes it pretty apparent that all three of them were there for a reason. At least that's what it seems like to me. Poirot ran into an acquaintance, the director of the company, only an hour before boarding the train. Poirot also knew ahead of time that M. Bouc was going to be leaving a first class cabin to stay in a second class cabin with Dr. Constantine. Then, when a murder inevitably happened the three of them proceeded to become the investigative team taking all of the evidence from the other passengers.

I guess I'm not as much asking a question as I am making a theory. Is it possible that all three of them knew that something suspicious was going to happen beforehand, and therefore ended up on that precise passage? If we are not to believe this then we have to believe the fact that the only passenger in the Calais coach that wasn't part of the team planning the murder was possibly the best criminal investigator in the world. I mean, that's some extremely bad luck for the rest of them.

Maybe it's just for plot conveniences. I looked up some wiki pages for other Agatha Christie novels about Poirot, and in "Death on the Nile" Poirot is somehow on a cruise ship when a murder happens and then investigates the passengers there. This is the first Hercule Poirot novel I've read and it's actually the first murder mystery novel I've ever read, so maybe this is common in Agatha's novels. Still that part of the story bugs me in a way because it seems either unbelievable or it seems that there was a greater understanding behind all of it that was never explained.

With all that being said, I really loved Murder on the Orient Express and am definitely going to read more Agatha Christie novels.

Does anybody else have similar thoughts after reading the book, or possibly an explanation as to how I'm wrong? Lol