Johnny Sonata Techno-Remix
It all started when Hardcase contacted you about a horde of Wailers attacking a warehouse in The Hard Way. Investigating, you found a gang of Freakshow with sound modifications being swarmed by Wailers. After you dealt with the situation, you found a bunch of music discs on the Freakshow, including a techno-remix of Johnny Sonata's greatest hits. Hardcase speculated the Wailers were attracted to the music!
Hardcase saw this as an opportunity to draw the Wailers away from St. Martial. He sent you to go after Trey Belcleff, one of the Freakshow's sonic techies. Getting to Trey, you got him to build a sonic transmitter capable of attracting the Wailers from a distance.
Hardcase picked a target for the sonic device: Paragon City. You snuck over to the mainland and planted the sonic transmitter in the sewers beneath Paragon, avoiding patrols of Longbow who caught word of your presence. You managed to plant the device, giving a momentary reprise from the Wailers for St. Martial.