Lydia Evergreen doesn't believe in coincidence—only cause and effect. So when half the university's population vanishes without a trace, she refuses to believe it's an accident. The anomaly defies logic, but one thing is clear: it's connected to her work. And Ray, her closest colleague, is among the missing.

With time running out before the unstable rift seals itself forever, Lydia crosses into the unknown, a world that mirrors her own in eerie and impossible ways. There, she comes face to face with unsettling versions of the people she thought she knew—including a dangerous figure from a world where knowledge is ignored, and those who seek it are seen as a threat.

Can Lydia prevent him from breaking into her world? Or will stopping him require the ultimate sacrifice?