Aria is staying at her parent's house before she gets her own apartment. After breaking up with her boyfriend, since she had no idea where she would stay, her parents invited her to stay at their place before she got on her feet. With her parents going on a cruise, she jumped on the offer to be able to lick her wounds in peace without her parent's interference and to take her time to figure out things. That night, after she'd just moved into her parent's place, she is tired and just wants to rest. That's where she has her first encounter with Callum. She goes over to his house to ask him to turn down the music because it's too loud, and there she finds him shirtless. She was hoping to have a peaceful night but that's out of the window because of the noise.
At work the following day, Monday, even though she didn't have enough rest, she is in a good mood because she is hoping to be promoted to Marketing Director. She heads straight to the conference room and finds her boss and her boss's boss, and a few minutes later, Callum walks in. She is quite surprised to see him, and when she is told that she won't be getting the promotion and that Callum would be the one taking over, she is beyond furious. She hates him more than ever for taking her spot. And to make matters worse, they would work on the same project together.
Come Monday at work he is shocked to see her walking into the conference room and feels bad for her when he realizes he took her promotion from her. When they are assigned to work together, he doesn't know whether to be grateful for the opportunity to be closer to her or not. He senses that she hates him, and he doesn't try to make her see he isn't a bad person. He actually loves the banter they have.