The "darkness" in the title refers to the hidden parts of the human soul. Every character keeps secrets—affairs, lies, and betrayals—that act as the fuel for the cycle. The show posits that as long as humans are slaves to their desires ("Man can do what he wills, but he cannot will what he wills"), they are doomed to repeat their mistakes in the dark.

Led by Eva (an older Martha from a parallel world), this group fights to maintain the cycle, ensuring that every tragedy and every birth—including her own son’s—happens exactly as it always has. 4. The Origin (The Third World)

When a child goes missing in the small town of Winden, four families embark on a frantic hunt for answers. What they find is not just a kidnapping, but a generational conspiracy involving time travel, hidden identities, and a battle for the soul of time itself. 1. The 33-Year Cycle

The primary "secret" governing Winden is the lunar-solar cycle. Every 33 years, the stars and planets align in a way that allows the past, present, and future to influence one another. This creates a closed loop where events in 1953, 1986, and 2019 happen simultaneously, making it impossible to tell where the "beginning" truly lies. 2. The Identity Paradoxes