Please answer the following question: Given the following context:  Chicago DEA agent John Hatcher returns from Colombia, where drug dealers killed his partner Chico. As a result of Chico's death and years of dead end work, John retires and heads to his family's home town of Lincoln Heights in suburban Chicago. He visits the local school to meet his old friend and former U.S. Army buddy Max who works there as a football coach and physical education teacher. As John and Max celebrate their reunion at a club, a gunfight breaks out between local drug dealers and a Jamaican gang at the venue. The gang, known as the Jamaican Posse, is led by a notorious psychotic drug kingpin named Screwface full of West African Vodun and sadism. John arrests one of Screwface's henchmen as the gunfight ends. News of Posse crimes occurring in Chicago and across the United States spread as the Posse expands its operations and recruits more members. The next day, Screwface and his henchmen do a drive-by shooting on the house where John, his sister Melissa, and Melissa's 12-year-old daughter Tracey live. Tracey is injured and hospitalized in critical condition. John encounters a gangster named Jimmy whom he is forced to kill. A Jamaican gangster named Nesta arrives and is subdued by John, who asks about Screwface. Nesta gives information but tells him to go after Screwface alone and jumps out the window to his death. The next day, John discovers a strange symbol engraved on a carpet, and with the help of Jamaican voodoo and gang expert Leslie, a detective for the Chicago Police Department, he learns that it is an African blood symbol used to mark their crimes. John decides to come out of retirement to join Max in a battle against Screwface.  answer the following question:  Who does Melissa's sister come out of retirement for?
A:
Max