In the world that Isabel J. Kim creates in Sublimation, when someone crosses a border with the intention of leaving their home country to live in another nation, they split in two. One self remains, the other moves on into a new life, taking on another "settled culture with intent” and severing “the self from the self.” One person becomes two, like identical twins or physical clones, yet they’re separated by different environmental and societal influences.

In Kim's world, this has existed forever, or at least since 1753 B.C. when it was mentioned in Hammurabi's Code of Laws. It's called "Instancing" and the divided selves are known as "instances." They can be reunited in an act known as "reintegration," when two instances touch, skin to skin. But, as Soyoung wonders in a Seoul shopping mall where she meets her friend Yujin, a man who is also an instance, is this act of reintegration "emotionally equivalent to murder?"

She has reason to wonder. Her grandfather, on his deathbed, issued his last request: that she and her instance, Rose who lives in Brooklyn, reintegrate. Soyoung has told Rose that their grandfather has died but fails to mention his dying wish, not even when the two of them meet for the first time in Seoul at his funeral.

Their two selves are far from compatible and the two women have jagged encounters. Yujin is the one to tell Rose what the grandfather wanted. When she's given an envelope with the deed to the family home, willed to her by her grandfather, the tensions between the two women heighten and in a moment of rage, Soyoung grabs Rose by the hand. They merge into one body but their separate beings and their separate remain intact.

YJ, Yujin’s instance, works in a New York high-tech firm and he’s told Yujin that he's working on something called Mitosis, which will reverse the reintegration process. The woman that's now a blending of Soyoung and Rose sets off to find this man so their two selves can resume their separate existences.

When Soyoung-Rose persuades YJ to let them become part of the Mitosis beta-testing, they learn it’s far more than just a reintegration process. Mitosis works through special gates that can both prevent and cause instancing. It can allow, or force, instancing and reintegration to take place. Its gates can create a border anywhere and it will soon be sold to the U.S. government. From there it will be put on the market to other countries as a state monopoly. Instancing and reintegration will stop being voluntary, except for those who can afford it.

"Instancing relies on the knowledge that you're never going to return, that you don't want to return...(Mitosis) decouples the action from the emotion."

Kim cleverly links the ethical and psychological implications of this to Eve and Adam biting into the apple of knowledge. Soyoung-Rose becomes aware that with Mitosis everything will change. No longer will people face the private question of "Do you want two selves?"

Sublimation is a thriller that goes for the throat and hangs on right up to its last word. But for some readers, it will go deeper, heading straight to the heart. For anyone who has left their birth country and made a home in another part of the world, the two selves created by instancing are very real, each one always painfully aware of who they are in another part of the world. As Kim shows in her stunning debut novel. those people have taken a bite from the apple of knowledge and will always live with the uncomfortable yet profoundly exciting result.