A teen-age girl named Cassie Reynolds appeared in Llanview in 1981, claiming to be Dorian Lord's daughter. Several months later, Cassie learned her birth father was classical pianist David Renaldi. Dorian and David had been involved when Dorian was attending medical school and she had gotten pregnant and had Cassie. David, who at the time was going under the last name Reynolds, took Cassie and left Dorian without a word, and she didn't know for years where her daughter was. David explained that he left with Cassie because Dorian expected his musical career to take a back seat to her medical one. David took Cassie to his mother's home and planned to return for her, but his musical career got in the way. Later, when he became involved in human rights work, he stayed away out of fear for her safety. When she arrived in Llanview as a teen-ager, Cassie moved in with Dorian. Dorian later married Herb Callison, who adopted Cassie..

In 1985, Cassie fell in love with Rob Coronal, who is part of an infamous mobster crime family. Her mother greatly disapproved and she confronted Rob and warned him that if he didn't immediately break his engagement to Cassie, she would tell the world that his father Alex Crown was alive. Rob gave in, but he and Cassie soon continued their romance in secret. When his father joined the Witness Protection Program they married as they had originally planned. But by 1986 the marriage had ended in divorce. Evil Mitch Laurence, meanwhile, was apparently killed while trying to rape Cassie. At first Cassie was implicated, but Dorian confessed to the crime and was convicted of Mitch's murder. Eventually Dorian was exonerated when a tape surfaced that proved the killing had been in self-defense (although it was revealed many years later that Mitch in fact had survived).

In 1987, Dorian left Llanview to become the U.S. Ambassador to Mendorra after discovering that Cassie was having an affair with Dorian's boyfriend, private detective Jon Russell. Cassie and Jon's relationship later fizzled and she reunited briefly with ex-husband Rob. Cassie left town herself in 1988 but returned three years later.

In 1991, Cassie began dating recently widowed Bo Buchanan and they quickly got engaged, much to the chagrin of Dorian. A former FBI agent, Alex Olanov, who pined for Bo attempted to drown Cassie and was sent to jail. On Bo's wedding day to Cassie, Alex found Bo's presumed dead wife Sarah Gordon Buchanan very much alive and brought her to the reception where she was reunited with her shocked family. Bo returned to Sarah and Cassie's marriage to him was annulled.

Cassie then married local reverend Andrew Carpenter in 1993 and soon became pregnant. In a mother-daughter confrontation, Cassie ordered Dorian out of her life for good. The heated exchange, in combination with Cassie's already high blood pressure and an accidental tumble down the stairs, caused her to go into premature labor. Little William Carpenter lived only a few hours before dying. The terrible loss drove Cassie's normally-placid husband Andrew to lash out at Dorian -- nearly strangling her to death! Cassie, meanwhile, found an abandoned baby in the manger outside St. James Church. The baby's mother showed up but soon died of an illness spreading throughout the town, with her last wish being for Cassie and Andrew to adopt the baby, who they named River.

The Carpenters' marriage seemed to be getting back on even footing as they focused on raising their new son, but when Cassie went back to work as a journalist at The Banner in 1997, she began a tempestuous working relationship with rival reporter Kevin Buchanan, one that slowly blossomed into mutual passion. Cassie broke her wedding vows and began an affair with Kevin, ruining her marriage and her reputation, even losing custody of River in the ensuing divorce and custody battle.

Cassie then embarked on a quest to discover the truth about the history of mental illness that ran in her family. The search led her to the home where her mother grew up in Canton, Ohio. Kevin risked his life to save Cassie from an inferno that burnt down the Cramer homestead and was badly burned. Wounded in the fire in Canton, Kevin became enamored of his hospital nurse, Barbara Graham. They had a brief affair that Kevin ended, but then Barbara developed an obsessive fixation on him.

Meanwhile, Cassie's long-lost father, David Renaldi, returned to Llanview, stricken with ALS, to reconnect with his daughter and new grandson. Jealous of the relationship between Kevin and his nurse, Cassie hired Barbara to be her father's live-in nurse so she could keep a close watch on her. Cassie found out that Kevin had cheated on her with Barbara and Cassie moved out of the house Kevin had bought for her and moved back in with Dorian.

Turning murderous, Barbara attempted to kill Cassie, whom she believed stood in the way of her future with Kevin. Barbara lured Cassie to the docks in the warehouse district of Llanview and attempted to gun her down; instead, she murdered Drew Buchanan and crippled Cassie, leaving her wheelchair-bound. Eventually, Cassie discovered that Barbara was the shooter, and her rage and fury left her mind once again unhinged. Cassie turned the tables on Barbara, blackmailing her with knowledge of her crime, forcing Barbara to participate in her wedding to Kevin and become Cassie's personal nurse. As Cassie slowly regained the use of her legs, she hid the truth from her friends and family. Finally, Cassie dragged Barbara to a bell tower at gunpoint, attempting to force her to jump to her death. Kevin and Andrew arrived just in time to stop Cassie. Cassie was institutionalized, and Barbara was arrested.

When Kevin and the family visited Cassie, they discovered she had suffered a full psychotic break, believing she was still happily married to Andrew. Andrew and Kevin both attempted to break through to her, to little avail. Dorian, who had never approved of Cassie and Kevin's relationship, in early 1999 decided to send Cassie to Switzerland for further treatment. Kevin fought her every step of the way, even stowing away on the private plane bound for Switzerland to try one last time to get through to his wife. In a brief moment of lucidity, Cassie begged Kevin to let her go. Heartbroken, Kevin returned to Llanview and agreed to have his marriage annulled.

Cassie returned to Llanview in late 2001 to attend her cousin Blair's wedding to Todd. Cassie explained that she was almost fully recovered and living in Switzerland with her son River. She even shared a somewhat awkward reunion with her cousin Kelly, who had since gone on to marry Kevin herself.

Fully recovered, Cassie next returned a year later, rushing to Blair's aid after she was apparently attacked by mob hitmen. Cassie believed Blair had been rendered catatonic, and was tasked to take her out of the country. In reality, Todd and Blair had used Cassie to lure away her supposed assailants with the help of a body double, while Blair hid out at Todd's penthouse.

While back in town for Blair, Cassie also recounted her harrowing experiences with Mitch Laurence for Viki and Bo. Nothing could have prepared her for the shock of her life when she returned the following March to see Dorian, only to discover that her mother was marrying the resurrected Mitch -- the man who had tried to rape Cassie! Cassie and Blair watched in shock and disgust as Dorian and Mitch took their unholy vows, and gained control of the Lord fortune. Cassie did not yet realize that Dorian was conning Mitch in the hopes of winning his trust and destroying him. Dorian haltingly tried to explain things to her daughter, but Cassie left town in disgust for her new home in Savannah. Later that year, on Mother's Day, Cassie and Dorian made peace after Cassie discovered Dorian and Blair's efforts to murder Mitch. Meanwhile, a now-teenaged River came home from Savannah to spend time with his father and grandmother. During this visit, Cassie also painfully reunited with Kevin and Kelly.

In the fall of 2003, Cassie was part of the Cramers' competition to win Aunt Betsy's inheritance, but was immediately disqualified due to her own "lapses in judgment" with Andrew and Kevin. In 2004, Cassie returned, furious about River's relationship with Adriana Colon, who had just been revealed to be Dorian's daughter and therefore River's aunt, albeit non-biological. She and Adriana eventually made peace, and Cassie returned to Savannah.

In February 2010, Dorian feared that her girls were in danger after Mitch Laurence resurfaced yet again and threatened Dorian's family. Dorian called Cassie in Savannah and begged her to call Blair, who wasn't talking to Dorian at the time, to make sure everyone was safe. Cassie also phoned Kelly and told her to take Dorian's warnings seriously. Once Mitch was safely behind bars, Dorian arranged for a reunion of the Cramer girls at La Boulaie. Kelly and Adriana already has arrived when Cassie arrived from Savannah with Andrew and shared the tragic news that Dorian's sister Melinda had died the previous night of a massive coronary at the clinic in California where she had been committed for years. Kelly was devastated to lose her mother, while Dorian was convinced that Mitch was behind her sister's death.