Premise: It's nothing much, but ”well, if you are going, will you tell him ” he dropped his voice to a whisper ”"I think I've found the extra coffee-cup!" I had almost forgotten that enigmatical message of Poirot's, but now my curiosity was aroused afresh.

Hypothesis: He told me to tell Poirot that he was still searching for the missing extra coffee cup. 
Relation: contradiction