Yesung is convinced that Ryeowook and Kyuhyun are in love.  He believes that the reason they aren't together is because he once dated Ryeowook himself and the two feel weird about dating while he's around.  So he has high hopes that something will happen between them when he starts his service time.  But it doesn't.  Now that he's come back home, he's determined to make the maknaes see that they're both in love with each other and need to stop wasting time and start dating.