Ian McAllister first appeared in Salem, hiding in Madison James's hotel room. When Brady Black came by, Ian let him in and introduced himself as Madison's husband. But, it was clear that Madison was very upset.
Madison had met Ian when she was very young and she fell for his charm. Ian was also her first investor in Mad World, helping to endure the success of her company. But Ian had many affairs during his marriage to Madison, including a passionate affair with Kate Roberts. Despite Madison's efforts to divorce him, Ian would not allow it.
Ian was in Salem for more than just Madison. He also accepted a new job as the CEO of Titan. Despite Brady and Victor's objections, Ian claimed that the contract was binding.
In addition to Titan, Ian was also in Salem for Kate. Kate and Ian had shared a romantic past together. With Stefano away in Alamainia, Ian made his move and showered Kate with gifts and attention. During a moment of weakness, Kate slept with Ian. When Stefano found out, he kicked Kate out and fired her from her company. Ian took Kate in and gave her a job at Titan -- head of Mad World alongside Madison.
Ian also set about breaking up Madison and Brady. Knowing that Brady was a recovering addict, Ian began slipping drugs to Brady -- first in Brady's drink and then in his protein powder. At first, Madison was sure that Brady was using again. But, after going to rehab with him, Madison believed Brady.
When they returned, they annoucned that they were going to marry right away. They set their wedding date for midnight, the night of Lexie's memorial autism fundraiser. However, there was a great explosion that night int he tunnels underneath Salem. Many buildings were damaged, including the banquet hall where Lexie's benefit was being held. Madison was fatally injured in the explosion. Ian was with Madison and held her in his arms while she died. He confessed his love for her and tried to apologize for hurting her. With her last breath, Madison lifted her head and said, "I love you, Brady."
Kate overheard Ian's confession and was furious. She followed Ian to his hotel room and they had a heated argument. Ian screamed at Kate, saying that he never loved her, he was just using her to get to Stefano's money. He also confessed that he was the one who "killed" Stefano. Ian left the hotel room and warned Kate not to follow.
It turned out that Ian's believed that his mother was romantically involved with Santo DiMera, thus making Ian a DiMera and so entitled to part of the DiMera fortune. So he staged Stefano's death so that he could kidnap Stefano and tortured Stefano into giving up the DiMera money. Ian also framed E.J. for the murder so that E.J. wouldn't come looking for Stefano.
But, when Stefano refused to spill any secrets, Ian kidnapped E.J. and planned to torture E.J. in front of Stefano. When Stefano said that he didn't care because E.J. wasn't his biological son, Ian confessed to planting the letter from "Alice" as part of the way to frame E.J. Thus, Stefano and E.J. really were father and son.
While Ian was looking away, E.J. got free and attacked Ian. When Ian was knocked out, E.J. tied up Ian and called the police. Bo and Hope arrived and took Ian into custody.