Dr. Arthur Cabot's name cropped up when Anna Devane was struck blind by a mystery virus that was traced to an experimental project on twins. Anna's sight had been restored, but she had an identical twin sister who had once worked for the DVX, so Anna was determined to get some answers. Anna decided to track down Dr. Cabot to find out what had been done to her. With the help of Dr. Hamilton Finn and Robert Scorpio, Anna discovered that Dr. Cabot had been living in Stockholm, Sweden.

When the trio arrived at the clinic in Stockholm, they were surprised to discover that Dr. Cabot was a patient not a staff member. Dr. Cabot was wheeled into the visitor's room and it quickly became apparent to Anna, Finn, and Robert that the doctor was blind. Finn asked about Dr. Cabot's blindness, and Arthur revealed that it had occurred suddenly a few months earlier. Finn concluded that the blindness had been a result of the "HN-242" virus, which had left both Anna and Kevin Collins temporarily blind. Each had been an identical twin. Finn assured the doctor that he could reverse the blindness with a simple procedure -- provided that Arthur cooperated.

Finn introduced Robert as his "Australian" colleague then explained that they wanted to know more about Arthur's research with identical twins. Arthur became suspicious when he heard Anna's voice because he recognized it. Anna claimed to be her identical twin, Alex Merrick, but Arthur knew it was a lie when she asked about the experiment. He realized that Anna wanted answers, and he agreed to help once his sight had been restored.

On February 18, 2019, Arthur's sight was successfully restored, so Anna demanded that he hold up his end of their bargain. According to Arthur, he had worked for the DVX with Alex, and Alex had been the perfect candidate because she had been an identical twin. Arthur explained that he had been studying the physical and emotional links between twins, so it had been particularly useful that Alex's twin had worked for the enemy -- the WSB.

Anna was not satisfied because she had no memory of participating in Arthur's program. Arthur conceded that Anna hadn't been a willing participant, but he assured her that she had been a part of the research. Arthur revealed that Anna had been drugged and abducted to "advance science" then he confided that all of his test subjects had received an injection that had infected them with the HN-242 virus. Furious, Anna demanded to know the purpose of the experiments. Arthur admitted that his work had involved transferring memory from one person to another, but he promised that the method of extracting information had been painless.

Finn assumed that Arthur's experiment had failed since Anna didn't have any of her twin's memories, but Anna disagreed. Anna realized that Dr. Andre Maddox had taken Arthur's study and he had used it for his own procedure on Andrew Cain and his identical twin Jason Morgan, Patient 5 and Patient 6. Anna deduced that Ryan Chamberlain had been Patient 3, and Kevin had been Patient 4.

A few days later, Finn and Anna caught up with Arthur at Metro Court. Anna wanted to know if she had any of her twin's memories, but Arthur advised Anna to talk to Alex. Arthur excused himself because he had a plane to catch, but Anna introduced the doctor to Agent Gray, Arthur's escort to Steinmauer. Arthur was outraged because he had cooperated with Anna, but she advised him to call his attorney.

On July 31, Arthur checked into Metro Court and met with Dawn of Day cult leader Shiloh, also known as Hank Archer. Shiloh had stolen a flash drive that had Drew Cain's memories stored on it. He wanted to know if it was possible for the doctor to transfer the memories to Drew's twin. Shiloh explained that Drew had knowledge of a secret bank account with millions that Shiloh needed to access. Arthur agreed to help the cult leader for a price, but he warned Shiloh that he would need the proper equipment. Shiloh was confident that he could provide Arthur with everything that he needed, but he worried that Arthur might have some qualms. Arthur assured Shiloh that he wasn't bound by any ethical restrictions.

Later, Arthur had an encounter with Finn at General Hospital. Finn immediately became suspicious because he couldn't imagine why Arthur would return to Port Charles if he had secured his release.