A poisoned collar forces you to trust five strangers you have no reason to believe in. The show takes that premise seriously, making every alliance feel dangerous instead of convenient. By the time you realize who actually has your back, the city's chaos has already reshaped who you are willing to become to survive it.
Shinjuku descends into terror as an underground organization wages systematic violence against the city. When police officer Ichika Hoshino becomes collateral damage in their campaign, she wakes with a poisonous collar locked around her neck: a countdown to her own death, a message, and a problem with no obvious solution. Forced to hunt for answers that might save her life, Ichika encounters five men operating in the shadows of Shinjuku's criminal underworld. Each claims to want to help her uncover the truth behind the collar and the conspiracy threatening to consume the city. Each has their own reasons for getting involved, their own secrets, and their own agendas that may or may not align with her survival. As Ichika races against time, she must navigate which of her unexpected allies can actually be trusted. The investigation pulls her deeper into a web where innocence is a liability and every connection cuts both ways. Solving this mystery means confronting uncomfortable truths about the men around her and about Shinjuku itself.