Chrissie is a popular girl and is very fashion-conscious. She is often found wearing stylish clothing. In the beginning she is selfish and arrogant like Simon, but, like Simon, she reforms herself and day by day she cares more about her friends than herself.
She is love-struck by Simon and only went on the trip to get to know him better, but she wasn't prepared for what would really happen. Simon, however, shows an interest in Sarah from the start, leaving Chrissie feeling alone and as an outcast, something she is not used to. Simon doesn't seem to notice Chrissie's suggestions until later on, when he needs her help. When Sarah is clear she isn't interested in Simon, he tries to make a relationship with Chrissie, but she, after seeing his true colours, isn't bothered about him anymore.
Harry makes her realise that she still does like Simon, especially when they lock him in a train overnight. In the third series they get back together and have their first kiss. She was responsible for losing the anti-venom because she was jealous of Shona. Chrissie is the third to get the red eye virus.
Red-Eye: After their brief visit to the hospital and retrieving Gerry's file, Simon and Chrissie continue their search for the mysterious A.S.T.R.I.D Island when Simon spots Harry panicing in the distance. Harry and Lucy are being pursued by Stanich when a large truck hurtles towards Lucy on the busy main road. Chrissie reaches out and pulls Lucy back, saving her life. But then Chrissie's eye turns red, she splits into two and vanishes. And Harry is the only one that saw it happen.