You start this mission at the GCPD but you don't actually do anything until you receive your first call at the Museum. The first call will give you a minute to reach the northern part of the city
Monarch Theater - This phone will bring you just north of the Steel Mill by two buildings. Just keep this in mind when navigating so you don't bump into the restricted area.
Industrial District - Head north from the front gate of the Sionis Steel Mill. The phone should be in the vicinity of the ferris wheel. This phone will take you to in front of the GCPD building.
GCPD - Later, you will be able to receive a call here. This will lead you all the way across town to the Museum
Park Row - East of the Courthouse under the bridge. This phone will lead you to the Northeastern part of the Industrial District, east of the Catwoman building.
Amusement Mile - If you walk out of the GCPD and follow the street in front of it to the T-intersection, there should be a phone by the building direclty in front of you. This phone will take you west of the courthouse.
Park Row - West of where it says Park Row and north of where it says Bowery on the map, at the corner of the two streets. Goes to SE corner of the Catwoman building in the Bowery.
Bowery - The Southeastern most point of the Bowery, butting right up against the Restricted zone. This will take you to NW of the Steel Mill.
Once you've done all these, you will find Zsasz North of the Steel Mill and just south of the bridge. Once inside the building, walk towards the next door and turn right to see a vent high up on the wall. Use the batclaw to pull it down, grapple up and climb through the vents.
Once you reach the other side, follow the simple path until you come to a few pipes that you can slide under but don't. Wait for the water level to rise, throw an Freeze Blast onto the other side, then slide through. Wait for the water to go down and grapple up to the other side. Jump over the saw and then make a raft here and use the anchor points to pull you over. Climb up the other side and walk up behind Zsasz. Do a takedown through the glass.
