What if a lucid-dream experiment didn't just alter your mind, but trapped you in another world? Neuroscience PhD candidate Astra Rowe recreates a forbidden experiment to escape the manipulative relationship controlling her future. Instead of entering a dream, she fractures reality and awakens in Lucidium, a sentient realm where subconscious desires turn deadly. Every visitor from Earth is hunted by a Doppelgänger born from their deepest guilt. In Lucidium, confronting the self is the only way to survive. Fail, and it consumes you. The only person who understands the rules is Cinder Vaylen, a physicist trapped in Lucidium since 1950, his body frozen at the age he arrived. But Astra's arrival begins to unravel the fragile control he has fought to maintain. Worse, her Doppelgänger wears the face of her dead twin sister. As Astra and Cinder search for a black hole portal that may lead home, their growing connection begins to destabilize the world around them. Because Lucidium feeds on emotion. And when Astra's obsessive professor follows her into the realm, the life she tried to escape collides with the nightmare she unleashed. To survive, Astra must confront the darkest parts of herself... even if escape means becoming part of Lucidium forever. Lucidium is a dark, psychological, romantasy about obsession, consciousness, and the price of love.