Olivia and Thalia are college roommates and they're introduced in the story as they first meet eachother on move-in day. Thalia comforts Olivia when she notices she is homesick, and they decide to decorate their dorms and they get to know eachother and stuff. One night Thalia tries to get Olivia to open up a bit, and so Thalia starts talking about her life back home. She mentions she was in a relationship with a girl, which gets Olivia's attention. This is when Thalia learns more of Olivia's family and her parents.
During Christmas break, Thalia actually gets sick. Thalia says it's a good thing Olivia is going home for the holidays, so she won't get sick herself. Olivia then concludes Thalia never talked about going home even before she got sick. Thalia admits she had nobody to go home to, but Olivia says "you have me." and Olivia ends up staying on campus for the holidays.
Then, at a party, Olivia sees Thalia make out with a guy and she gets totally confused. She then realizes she is also a bit jealous, and admits she may have feelings for Thalia. As Olivia is outside after having left the party, there is an explosion at the party due to a gasleak. Olivia finds Thalia on the way out, presumably following after her, which paramedics say saved her life.
In S2 Olivia notices Thalia starts to sleep through classes. A few days, a lot of Thalia's clothes are gone and Olivia is about to report her missing when Thalia texts her she is with her family, causing Olivia to be more confused because she believed Thalia had none. Thalia then reveals she does have family, but that her parents are very controling. When Thalia's mom starts calling Olivia, Thalia and her mom have a fight. When -in the middle of the fight- the mother asks Thalia if she was falling for Olivia, Thalia replies with yes. She then takes her stuff and returns to uni. Thalia arranges a movie-night upon her return, during which the two of them first kiss.
Thalia then suggests going on a vacation in spring break, which Olivia declines because their relationship is relatively new. The following morning Olivia finds Thalia with her wrists cut. She gets taken into the hospital, where Olivia goes to visit. Olivia then catches a medical chart and googles the medecine. Olivia soon concludes the medecine is prescribed for managing bipolar disorder. Thalia admits she is bipolar, and states she didn't want to feel unwanted anymore. Olivia confirms she still wants to be with Thalia, despite the new information. Olivia makes it a priority to learns as much as she can , and she helps Thalia with her meds from there on..