Viola decides to disguise herself as a boy names herself Cesario, and delivers Orsino's love letters to Olivia
Viola falls in love with Orsino, Orsino falls in love with Olivia, and Olivia falls in love with Cesario
Olivia confesses her love for Cesario, and Andrew wants to fight Cesario for Olivia
Instead of Cesario Sebastian, his (her) lookalike switches places and beats Andrew. Olivia falls in love with Sebastian, and Sebastian loves her riches so he stays with her
Sebastian and Olivia happily marry, and Cesario can go back to being Viola and her and Duke Orsino get married
