As Tears Go By movie plot

Ah Hua and Ah You are two gangsters in Mong Kok, and they are brothers and sisters. Ah Hua has been involved in the underworld earlier and is tired of the fighting at River's Lake , but Ah You has always dreamed of being a "leader" one day. The top spot, but Ah Hua has been protecting Ah You everywhere, so that Ah You has no chance to perform. One day, Ah Wah's cousin Ah Yu came here from Lantau Island for medical treatment and temporarily stayed at Ah Wah's house. The two fell in love with each other. At this time, Ah Wah was also busy taking care of Ah Yu who was injured in bed, so she didn't have time to be with Ah Wah. Two days later, Ah Yu returned to Lantau Island, much to Ah Hua's chagrin. Later, regardless of his gang status, he rushed to Lantau Island to express his love to A-Yu. Unexpectedly, at this time, in order to make a name for himself, A-You actually accepted the "killer order" to die alone. A Hua who got the news hurriedly bid farewell to A Yu and rushed to the scene. Ayou shot and killed the target of the "Killer Order" at the gate of the police station. He was besieged by the police and died after only one shot. When Ahua arrived, he saw Ayou lying on the ground, and he took it out without hesitation. The gun killed the target person, and he was shot dead by the police on the spot   .