Slicks—portals to an alternate world—show up in our world. The world they lead to is hauntingly empty of human life, although it is full of buildings and cars, and the fluorescent lights hum in grocery stores and strip malls.
Ian is one of the first people to have entered a slick. He makes a meagre living rescuing people who get lost in them. A journalist from the local alternative paper is interviewing him when Ian gets a call to rescue a teenaged boy. Jon, the journalist, follows him through the slick into the Other Side. Then the slick closes behind them. Ian explains that if they can find another slick, they can use it to get back home.
They find the teenaged boy. Then they find two women who also went through the slick and got stuck, Nomi and Karen. They all find a way back.
So begins a strange friendship, as now three of them—Ian, Jon, and Nomi—venture to the Other Side. Ian wants to stay on the Other Side, Jon wants to understand the Other Side, and Nomi wants to explore it. Ian is not so comfortable with Jon making his life into a story, and tensions build. Then Nomi gets stuck on the other side again, and becomes too scared to continue.
Jon, working with a physicist to try and understand more about the slicks and the Other Side, comes to believe that Ian is somehow a kind of unwitting catalyst to the appearance of the slicks. Ian feels trapped and accused and flees to the Other Side, swearing he will not come back. Nomi wants to chase him but is too afraid.
Ian has a choice; our world or the Other Side. He decides that he will abandon the world of the slicks, and make his stake in our world. But across the world a few other people are also discovered to be catalysts for slicks. Different slicks, to different worlds. Slicks, and the many alternate worlds they reveal, are a part of life now.