MOST WANTED: Lamb To The Slaughter
Objective: Investigate the Lady of Gotham and bring Jack Ryder to safety
After triggering this quest, you need to head to the Lady of Gotham Island (the small island in the center of the main three) to find a ritual in progress. You can listen to the sermon if you wish. When you are ready/bored, grapple over the fence and float down to the floor of the pit in front of the metal wire cage. You will have to fight a whole lot of guys within a time limit, so take advantage of special takedowns, counters and quick downing attacks to finish them off..
When they are all downed, you will have your time limit reset (up or down to forty seconds). Underneath the madman are four electrical generators that you will need to overload. Use the Remote Electrical Charge (RB) to take them all out. Once the electricity stops, use the grapple points on the left or right of the metal box to get inside and take down the mad priest. That's it for this sidequest 'chain.' Short one wasn't it?