Sentence:  [H]e sat down and we got into conversation. There wasn't time to talk much. . . . We got along famously. But—oh, well, it was just another case of <WSD>ships that pass in the night</WSD>. 
Meaning of the word marked with <WSD> tags:  Two or more people who encounter one another in a transitory, incidental manner and whose relationship is without lasting significance; two or more people who almost encounter one another, but do not do so.