Despite it being a good professional move, Mary is unbelieving that Rhoda has accepted a job at Bloomingdale's in New York City. Mary doesn't believe that Rhoda would give up her Minneapolis life just for a job. Even as Rhoda prepares for the move including packing and letting Phyllis show her apartment (including to one person who Mary does not relish thinking about as a potential neighbor), Mary doesn't believe it's going to happen and that Rhoda will eventually change her mind. But as Mary takes Rhoda on a bon voyage dinner the day before she is scheduled to leave, Mary comes to the true realization that Rhoda may actually be leaving. So when Rhoda makes an announcement mid dinner, Mary has to figure out what to do about what will be happening at her apartment later that evening. Meanwhile, Ted thinks he's met a woman who likes him and who he likes in return. He therefore gets quite a surprise at the end of their meeting.
—Huggo