Colleen Carlton found herself being drawn to her college art history professor, Adrian Korbel, and she became his research assistant. Finding themselves trapped together at the college during an ice storm, Adrian and Colleen made love in his office. Colleen was wracked with guilt, and tried to break up with her boyfriend, J.T., but since she didn't tell him about Adrian, he didn't let her. Colleen then quit as Adrian's RA, and they admitted that being together was wrong as student and teacher. Adrian seemed to have moved on by bedding Amber Moore, but was still drawing sketches of Colleen and remembering their time making love together.
Colleen, J.T., Victor Newman, and Colleen's father, Brad, became involved in the life and death hunt for the Grudgeon Reliquary, including Brad's past and Nazi-hunters. [See Colleen's profile for the full story.] In the end, Victor and Brad posed as art connoisseurs searching for the reliquary. After some tense moments they managed to fool some art thieves and purchased it. They brought it home to Brad's mother, Rebecca, who found an inscription which was in code. Thanks to Colleen confiding in Adrian, he solved the puzzle which revealed a treasure worth billions that was concealed in the catacombs in the Czech Republic.
Jana Hawkes suddenly disappeared, and so much of her blood was found in the park, she was feared dead. Surprisingly, Jana had been saving up her blood to set this all up. She kidnapped Colleen so that Jana and her father Milan could get to the Nazi treasure in the Czech Republic before Brad and Victor. Once she had the secret code from Colleen, Jana admitted that her great-grandfather, a jeweler, had been forced to etch the inscription into the reliquary, and then afterward, he was murdered by the Nazis because he knew too much. Then Jana trapped Colleen and Kevin in a walk-in cooler in an abandoned building and set it afire. Jana's father Milan turned up at the catacombs after Victor, Victoria and Brad had discovered the treasure. Milan locked them up, but was killed by the authorities, as he tried to escape with the treasure. Back in Genoa City, as the smoke got thicker, Kevin gave Colleen his water soaked shirt to help her breathe, they bonded, and were later rescued by J.T. and Adrian, but Jana had disappeared.
Adrian and Colleen went back to being together again secretly so that he would not get in trouble with the college, and she with her father who forbade the relationship. But Brad found out and Colleen stood up to him, moved out, and Brad cut off her funding and her car. Colleen's uncle Jack asked her to move in with him and paid Colleen's tuition as a loan. Adrian got an offer for a job at a prestigious museum in Paris, and they were all ready to leave Genoa City together. But Brad found out and got the job offer rescinded by donating a piece of art to the museum. Colleen and Adrian became openly a couple once he was no longer her professor, began living together in his apartment, and Adrian was writing a book on the Kunta Hora, which would tell of Brad's secret past. Colleen and Adrian became a couple openly once he was no longer her professor, began living together in his apartment, where Adrian was writing a book on the Kunta Hora. Jana had given Adrian information on Brad's secret past, and Colleen verified it, which threatened to put everyone in danger once again.
The time finally came for Adrian's book "SAVED: From the Ashes" about Brad's former life to be published, and he gave Colleen an advance copy to read. Though she had edited and consulted on the book, she had major regrets and fear for her family once she saw it all there in black in white. She gave the book to Brad, and he used his power and money to stop its publication. Adrian was enraged and felt betrayed since she had encouraged him all the way to tell all. Colleen took an offer she had gotten to do a work-study program, and seeing her relationship with Adrian in ruins, said good-by to her father and left for Beijing, China. Upon her return, Adrian was willing to forgive and forget, but Colleen broke off the relationship, and Adrian moved to Maine.
A year later, Adrian somehow found out that Colleen had died, and although unable to attend her memorial, phoned Traci with his regrets.