In Twelfth Night, the two identical twins, Viola and Sebastien, are shipwrecked and wash up separately onto the shore of Illyria. Viola assumes her brother must have drowned and wonders how she'll be able to survive in a strange place on her own. With the help of the ship's captain, she comes up with a plan: She will disguise herself as a boy and work as a servant/confidant of the Duke Orsino. The Duke is in love with a noblewoman named Olivia, who is mourning the death of her brother (unlike Viola's situation, this is a real death), and thus will accept no "entreaties" regarding love or marriage. So Orsino, impressed with the sensitivity and intelligence of his new worker Cesario (Viola's assumed male name), sends him/her to plead his case to Olivia. What ends up happening of course is that each person falls in love with the one they can't have: Olivia falls for Cesario, Viola for Orsina, and Orsino we already know about.

It's an extraordinary plot in every sense of the word. But to spend time considering its plausibility is an error, because its point is to allow the characters into worlds and ways of thinking that would not be possible otherwise. So Cesario/Viola engages in thoughtful discussions regarding the nature of love with both a male and a female. She herself is forced to consider it from fresh vantage points. And she takes the audience along.

In Shakespeare, the stories and so forth are always secondary to 1. the dramatic power of the scenes 2. the insights that can be found into human nature. With lesser literature, there is no larger payoff with which to mitigate hard-to-believe stories, but with this writer that's not the case. And even with unlikely plots like this one, the results of the exploration of thought and emotion are very easy to accept.