Quiz(2000)

Quiz is a Japanese thriller series centered on a mother's desperate search for her kidnapped son after a cryptic note arrives: "This is a quiz." Chief investigator Kaoru Kiriko of the Special Investigation Team pursues a trail of increasingly complex riddles designed to taunt the police. Street-smart and sharp-minded, Kaoru matches wits with an elusive kidnapper, but as she closes in, the tables turn—she becomes the hunted. The series unfolds as a fast-paced whodunnit where each puzzle deepens the mystery and raises the stakes, blending psychological tension with stylish crime drama as Kaoru races against time to uncover the truth before it's too late.