When the paths of a gifted female student, a cellist, an autistic teenager, a police officer, a prostitute, a teacher and a dog are entwined the very night a human head is discovered, attempting to crack the intriguing case leads to keywords all starting with the letter G. As the investigation continues, the complexity of the lives of Hong Kong people, the desperation faced by both locals and immigrants living in Hong Kong today are slowly uncovered and a suspenseful multifarious Hong Kong story is revealed.