On Finnea Prime, she was a net-girl, using the dataport installed on her neck. Through this, she met Draim, who specialized in blackmail and extortion. She worked with him, tapping into computers to get information about people. At first, she separated herself from the actions Draim took on the information she provided, often a mysterious disappearance. Over time, however, the consequences troubled her.
In 2373 she tried to leave the Syndicate. She came into contact with Tauvid Rem, who claimed to have a method to leave. They agreed to meet on Deep Space 9, and so Arissa went to Quark's. There, she met and impressed Chief of Security Odo with her keen observation of Dabo table manipulation via a graviton emitter. Meanwhile, however, Rem was killed by men loyal to Draim, Traidy and Sorm. Because she could not locate Rem, she tried to break into the station's computer, during which she was apprehended by security personnel and brought to Odo for interrogation.
Arissa, avoiding suspicion, claimed Rem had information on her long-lost daughter. When Odo checked her story, they found that Rem was dead, but otherwise believable. Later on, Odo, on a hunch, caught her on the Promenade when she broke into the assay office. When asked if she found anything in Rem's locker, she showed him a data crystal. In order to protect her, Odo had her stay in his quarters. Since first meeting, both had a mutual attraction for each other, and they spent a passionate night together. In the meantime, Starfleet crew studied the crystal to find out what the information was.
Having possession of the data crystal would allow her to contact Draim and offer it in exchange for her life and an exit from the Syndicate. She then stole it from the science lab and contacted Draim. He agreed to the deal, but wanted her dead anyway. He instructed his hit men, to kill her after the crystal was retrieved. They arranged a meeting in a cargo bay. Fortunately for her, another Idanian operative had arrived and helped Odo locate and rescue her from the assassins. The officer would reveal to Odo her real identity.
With the help of Doctor Julian Bashir, both the agent's real memory and Idanian appearance were restored. She said goodbye to Odo, and confided that, even though she was married, the relationship between him and Arissa was real and she would never forget him. (DS9: "A Simple Investigation")