Mari Jo Mason was head of the the Jabot Cosmetics art department.
In early February 1994, a mysterious woman contacted Blade Bladeson and told him she read about his upcoming marriage to Ashley Abbott and wanted to see him but he refused. Later, Blade couldn't identify the “Mari-Lyn” who sent him and Ashley a painting as a wedding gift. Afterward, Blade told Marilyn not to call him again. In time, Marilyn met Ashley's brother, Jack Abbott, and told him her name was Mari Jo Mason. Ashley credited Jack’s new upbeat manner to the mystery woman he was seeing and then suggested that they, Blade and Jack’s new lady have dinner one night.
Mari Jo called Blade and he warned her not to call again. Blade was stunned to see Mari Jo was actually Marilyn. Blade became concerned with Mari Jo's growing presence in his and Ashley's life while her relationship with Jack grew more stronger. Blade threatened Mari Jo to go to Jack about her and she reminded him about his brother’s death. Bent on causing trouble, Blade's former lover Mari Jo Mason, accused Blade of fighting with his twin brother Rick and leaving him to drown.
Blade later muttered that he didn’t believe Mari Jo’s assertion that he left his brother to die. Blade told Mari Jo to leave town within four weeks or he’d tell the Abbotts everything about her.
Mari Jo surprised Jack by proposing to him. Ashley started becoming suspicious of Mari Jo after noticing Mari Jo’s driver’s license identifying her as Marilyn Mason. Later, Paul Williams agreed with Ashley that the “Mari-Lyn” on the mystery wedding gift painting was similar to Mari Jo’s signature. Blade and Mari Jo admitted they were once lovers while Ashley felt they were still keeping something back. Months into her relationship with Jack, Mari Jo picked up fast jealousy when she spotted him around other women.
In the fall of 1994, Rick Bladeson, Blade’s twin brother, told Mari Jo not to reveal that he was still alive. Eventually, Mari Jo started consulting with him about Blade and the Abbotts. It wasn't until Blade's funeral that Mari Jo told Ashley via Jill Abbott that she was living as a wife to Rick for months. Mari Jo wasn't pleased to learn of Luan Volien's return into Jack’s life. She began to worry about the impact this reunion would have on their relationship.
Luan married Jack. Keemo Volien Abbott became romantically involved with his father's ex-fiancee Mari Jo. Keemo quickly tired of Mari Jo's mind-games and ended the relationship after she paid a prostitute to sleep with him. After grieving over Luan's death for several months, Jack resumed his relationship with Mari Jo. By summer, Jack and Mari Jo were again engaged to marry. Keemo sent Jack a fax urging him to be leery of Mari Jo.
Later Mari Jo helped Jack get over the tragic death of his wife Luan, but became obsessed with him. Then Victor Newman was shot. Mari Jo turned out to be the culprit after first framing Jill for it. Mari Jo had felt the only way to keep a FAX from Keemo detailing all her misdeeds from falling into Victor's hands was to shoot him. The recovering Victor suspected Mari Jo, so led her to assume his attorney Christine Williams had a copy of the fax so Mari Jo drugged Chris and held her prisoner in the Jabot prop storage room. Victor and Paul Williams tracked Mari Jo to Chris thanks to a tracking device they planted on Mari Jo. They arrived just as Mari Jo shot Chris with blanks from a planted gun. Mari Jo was institutionalized for attempted murder of Victor and the kidnapping of Christine.
Blackmailed blade bladeson
Had Keemmo abbott raped
Shot Victor newman
Framed Jill Foster abbott for shooting Victor
Drugged Christine Blair
Kiddnapped Christine Blair
Fired two shots at Christine Blair