Deep in the outback of China, prisoner 3424 is released from camp and seven years of gruelling work in the mines. A young man named Lin, he was imprisoned for activism in the protests at Tiananmen Square. His student ideals were crushed, and now he makes his long way back to Beijing. In the heart of the city, private detective Mei Wang is hired on the case of a missing person by talent magnate Mr Peng, a contact of her glamorous sister Lu. The subject in question is Kaili, a gorgeous young pop star, whose life was not as glittering as it first appeared. As the case rapidly slides into murder, Mr Peng chooses a corporate cover-up over the risk of finding out too much of the messy truth.But Mei is compelled by her instincts to do just that, and is drawn on a trail that takes her from the high rises and boulevards into the old hutong district, where superstitions are very much alive. Following a mysterious clue in a beautiful handmade paper butterfly, she uncovers events that take her back to her own memories of the heady days of Tiananmen that ended so brutally. Mei was lucky - Lin not so - but she plunges into the risky game of investigating the truth in a new society still catching up with the secrets of its past.