At lunchtime, passengers begin arriving in the dining saloon. Tim is grumpy with Mrs. Allerton about being caught up in the murder investigation, although Mrs. Allerton considers their involvement only a technicality. They talk about Linnet’s pearls, with Mrs. Allerton suspecting they are part of the crime and Tim arguing it’s probably something totally unrelated.
The dining saloon is where Race is going to conduct his search for the pearls. Tim’s insistence that the pearls have nothing to do with the murder is suspicious, given his own proximity to several missing jewelry cases.
Poirot comes to sit with Tim and Mrs. Allerton. They talk about Simon and how he’s recovering. Poirot talks about Simon’s strange psychology: he was bothered by Jacqueline stalking them, up until the point when he got shot, when suddenly all his anger seemed to go away.
Poirot has picked up on Simon’s odd behavior. Again, for someone who was recently shot and who claimed not to care about Jacqueline when he married Linnet, he seems to be on strangely good terms with Jacqueline.
Poirot then asks Tim if his cousin Joanna Southwood resembles Linnet at all. Poirot then adds that he’s been following Joanna in the news. Tim asks why—but before Poirot can answer, Jacqueline walks in, and Poirot stands to greet her. As Poirot sits again, he murmurs to himself, “I wonder if all young ladies with valuable jewels are as careless as [Linnet] was?” He then asks Tim if he has any previous experience being around during a robbery. Tim says no, but Mrs. Allerton corrects him, saying they were near a robbery. Tim disputes whether her version of the story is accurate but admits they were technically near a robbery at one point.
Poirot suspects that Joanna is involved in jewelry theft and that Tim is aiding her. While he’s delicate with his questions, and Mrs. Allerton doesn’t understand the subtext, enough information has been presented to make Tim a prime suspect for having stolen the pearls. His presence near other robberies (as well as his attempt to hide that from Poirot) only makes his proximity to this one more incriminating.
Poirot changes the subject to ask if either Tim or Mrs. Allerton has any experience with having packages shipped to them from England while traveling. They respond that, other than Tim occasionally receiving books, they don’t get any such packages.
Poirot’s other question about receiving packages is a little less clear, based on the information presented thus far, but it seems like he suspects Tim may have received a package related to the theft of the pearls.
While everyone is still in the saloon, Race makes a speech and announces the theft of the pearls, that he’ll be searching the boat for them, and that everyone is to stay in the saloon until the search is complete. Poirot pulls Race aside and whispers something to him, which Race agrees is a good idea.
As planned, Race begins a search of all the passengers while they’re still in the dining saloon. The book doesn’t reveal what Poirot says to Race in order to build suspense.
Just then, a steward enters and tells Race that Miss Bowers has asked to speak with him urgently. He and Poirot go to meet her in the smoking room. Miss Bowers opens her handbag and reveals a string of pearls.
Chapter Twenty ends with a twist—it turns out that the search for the pearls is unnecessary because Miss Bowers already has them. The chapter leaves off on a cliffhanger, as Louise was clearly involved in the theft of the pearls (and possibly Linnet’s murder), but it’s unclear how.