She was portrayed by actress Alyshia Ochse from 2011-12.
In late 2011, Ethan Lovett becomes fascinated with Wyndemere. While snooping around, he becomes suspicious that someone else might be snooping around there as well. At one point, he sees a woman, dressed all in white, but she won't speak and runs away. They start leaving written messages for each other however, and that is how they communicate at first. Ethan then becomes the caretaker of Wyndemere so that he has a reason to go there and find out more about her.
He then starts seeing her outside of Kelly's, but can never meet up with her. On January 3, 2012, Ethan's standing outside Kelly's and the Woman in White walks up to him and kisses him for New Year's, then walks off. Later, it's revealed that the woman is a patient of psychiatrist Ewen Keenan. The woman speaks for the first time on January 9, 2012, when she asks Ewen what's wrong with her. Ewen says that the woman doesn't know who she is, but there's nothing physically wrong with her. The woman then tells Ethan that Ewen calls her Cassandra because she doesn't know her real name. Ewen later tells Ethan that she doesn't appear to want to find out who she is. Ethan falls in love with Cassandra and they become lovers.
On February 5, 2012, Helena Cassadine comes to Cassandra and Cassandra claims that Helena has made her an assassin. She berates Helena for having had her locked up and hidden. Helena tells her that no one could know that she existed. They talk about how Helena wants revenge against the Spencers for the deaths of her sons, Stavros and Stefan. Cassandra says that Helena originally wanted her to go after Lucky, but since he left town, she wants her to go after Ethan instead. Helena's making Cassandra lure Ethan into a trap. Cassandra tells Helena that Ethan doesn't deserve what she's making her do to him.
On February 24, 2012, Helena returns and tells Ethan that it's time to end the charade. She makes Cassandra reveal that she is actually Irina Cassadine, Helena's daughter. Helena tells Ethan that she had Irina held in a compound and she tried to escape and nearly drowned. When she returned, she had great memory loss and so she told her what she wanted her to know. Irina says that Helena didn't tell her everything, so that's when she found Ewen to help her.
Ethan realizes that Irina has been conning him. She was to make him fall in love with her, but Irina says that she fell in love with him in the process. Helena then has her goons bring in Luke, whom she has been holding captive and beaten. She wants Irina to shoot and kill Ethan and make Luke watch, while she has him taped to a chair, for revenge for Luke killing Stavros (in 2001, though Stavros comes back in 2013 and later "dies" by the hands of Laura Spencer) and Stefan. She gives the gun to Irina to shoot Ethan, but she turns and tries to shoot Helena instead. Helena had anticipated that, and so she had given her a gun with blanks. She then has her goons shoot and kill Irina. Later, Ethan's mother, Holly Sutton comes and saves him.