Desmond was once a student of Dr. Richard Hammer. However, at some point, Desmond became an art dealer, to Richard's disgust, and the two became bitter rivals. Desmond was also secret lovers with Michelle. At some point, when Desmond discovered that Sara Wolfe knew where a valuable, ancient artefact called the Baphomet Idol was hidden, he tried to get her to cooperate with him.
Sara refused, prompting Desmond to shoot and kill her and fake Sara's death as a suicide. However, by this time, Sara had mailed Dr. Vannacutt's journal (which told the location of the Baphomet Idol) to her sister, Ariel. Thus, Desmond sent Michelle to seduce his former teacher Dr. Hammer, and he and his team tracked Vannacutt's journal down to Ariel.
Desmond and his team arrive at Ariel's house the next night, and after Desmond finds the journal and discovers from it that the Baphomet Idol is hidden in the Vannacutt Psychiatric Institute for the Criminally Insane on the coast of Los Angeles, he and his team abduct Ariel and and her co-worker Paul, and take them with them to the asylum. Ariel pieces together that Desmond is the one who killed her sister, which Desmond admits to without remorse.They arrive at the asylum to find that Dr. Hammer and his assistant Kyle are already there with Michelle, looking for the Baphomet statue as well. Desmond, Michelle and the team take Hammer and Kyle captive as well, and, after disabling the lockdown mechanism, set about searching the asylum's basement for the chamber where Vannacutt hid the Idol.
The team and the captives split up, and Desmond goes with Ariel. While Desmond and Ariel are searching the basement, Ariel is mysteriously dragged into a padded cell and locked inside. When Richard, Desmond and Michelle manage to break in, they find Ariel in a straightjacket and claiming that the house in indeed alive like Sara claimed. The group then return to the facility's lobby to find Kyle traumatized and Norris torn apart.
The lockdown mechanism then reactivates and seals the building, trapping Desmond and the others inside. Desmond is unable to contact Warren or Harue, but remains in denial that the house is alive, and insists that his team have turned on him so they can have the Baphomet Idol for themselves. When Ariel threatens Desmond with a gun for killing her sister, Ariel, Paul, Kyle and Richard turn on him and Michelle and capture them.
Ariel, Paul and Richard set about trying to escape the facility, and travel through the building with a captive Desmond and Michelle. While they are passing through the hydrotherapy room, Desmond and Michelle break free and Desmond pushes Kyle into the hydrotherapy pool. He and Michelle then flee with the map of the asylum and resume their search for the Baphomet Idol.When Michelle expresses less denial than Desmond that the house is alive, Desmond quickly accuses her of being part of the supposed plan among his team to turn on him, and chases her off with a gun.
Some time later, Desmond goes down to the asylum's crematorium to find Ariel, Richard and Paul have found the Baphomet Idol and are trying to flee with it. Desmond demands the Idol from the trio by threatening them at gunpoint, but at the last second before Ariel can hand over the Idol, two ghosts come up behind Desmond and take him by surprise. The ghosts lock Desmond in a furnace which then activates, incinerating a screaming Desmond alive.
Michelle was Desmond's secret lover, but he wasn't much less rude or cocky towards her as he was to others, and he tried to shoot and kill her when he became paranoid that she had turned against him.
Desmond did not express any sorrow towards Ariel for killing her sister, and even taunted her on it a few times. He also never took her seriously, even when she threatened him at gunpoint.
Desmond did not show any remorse or mercy towards Kyle when he threw him into a hydrotherapy pool.
Hammer and Desmond had a bitter rivalry, and Desmond not only abused Hammer for casually undermining him, but he also tried to shoot him at one point just for annoying him.