After a global catastrophe known as 'The Maelström,' where humanity suffered greatly, the World Health Organization rises to power, reshaping society to prioritize human well-being. In this new world, high school student Miach challenges the system's dehumanizing aspects before a surveillance system triggers on her 18th birthday. Planning a joint suicide with friends Tuan and Cian, their pact falters as Cian betrays them, leading to unforeseen consequences. Years later, now a Helix inspector, Tuan returns to Japan to investigate a sudden wave of mass suicides, uncovering a sinister terrorist plot.