The movie's development depends upon two mistakes

The movie attempts to be clever in orchestrating the tragic ending that happens but save for two incidents that are a problem, the movie may be almost flawless.

• The critical scene is when the main character, Chris, telephones his place of work and connects with his co-worker, curiously enough whose name is never given (I had to rewind the movie a couple of times to realize this; if I somehow missed the mention of this character's name, then give me the scene and the time index at which his name is mentioned).
His co-worker never made mention of the girl who was searching and asking about Chris. That clearly could not slip the co-worker's mind because the boss drove off with her to Chris' place, which by the way changed to being the hide-a-way boat in the course of scene changes.
Later when Chris arrives at the work, his co-worker wants to hint that this strange, young girl just happened to be there and Barry's animal magnetism persuade her to ride off with Barry to his hide-a-way boat.
What!?
The earlier scene was clear that she arrived searching and asking about Chris and the boss, Barry, offering to take her along to visit Chris at his home.
Was the co-worker deliberating trying to be generate separation between Chris and Barry?
Why did Chris not call Barry when Chris arrived at work?

• On a related note, when Barry and the girl, Jenny, drive off, that was a time for Barry to pass his mobile to Jenny for her to use and call Chris. In other words, in all that time that Barry was driving Jenny to Chris' house but instead they end up at his boat, there was able opportunity to call Chris (and leave a message if need be).

The second flaw/issue in the film is the inconsistent character behaviour.
• In one scene, Chris physical assaults Piers, the supposed Oxford uni student, who for some strange reason has such a lasting fatal attraction on Jenny which that alone causes questioning but suspension of disbelief is acceptable for that point, because Chris thinks Piers is somehow responsible for Jenny's absence.
So Chris acts aggressively to discharge the emotional frustration he experiences in missing Jenny.
Bare that in mind: Chris acts physically aggressive.
Later we have the scene in which Chris arrives at Barry's hide-a-way boat just in time to witness Barry's gentlemanly conduct towards Jenny. Granted we accept Chris' misinterpretation of the scene, but his reaction is inconsistent with his earlier behaviour: Chris runs away mad with anger, especially after first seeing Jenny after several days of not seeing her.
Humans react, especially emotionally, the same way regardless. That is the raw nature of a person, how they react emotionally. Here we are given two scenes and the character's reacts differently.


I do not know how the book is, but given the slow pace of the movie and the un-interesting characters, I am not inspired to read Pullman's literary creation.