There was a storm, and two twins were shipwrecked by the name of Sebastian and Viola.
''Wh-Where are we?'' She stuttered. ''My mistress, we are in Illyria.'' "What a beautiful place! By the way, where is my brother?" ''Oh, I saw the fine lad hanging on to a wooden plank. I was going to help him but the storm was too out of control. The lad should be all right, he is a strong young man." ''Who owns this land?'' ''Duke Orsino, Madam.'' ''Oh! I'll disguise myself as a boy and work for Orsino. I will be referred to as.. Cesario!''
Later that day, 'Cesario' was sent to the duke's love by Duke Orsino, to the say to her that the duke loved her so much. The duke's message was was rejected however, and she fell in love with Cesario. When 'he' left , he was adored by Olivia and was given a ring.
Later on in the story, Sebastian, Viola's sister comes to Illyria and has a duel with one of Olivia's kinsmen, Sir Andrew.
Sebastian is later on married to Olivia. Then Sebastian leaves and Cesario comes and Olivia says where have you been, and then Cesario said they never maried then Sir andrew comes to say that they had a fight then the real Sebastian comes in and apologies, all confusion ends.
Then Olivia married Duke Orsino like how Sebastian married Olivia and it was happy ever after.