Once you have defeated freeze, there will be a cutscene. Mister Freeze asks you to rescue Nora anyway, since that is all he has left. Batman's health is in critical condition, you must get the cure from the safe. Use the controls on Freeze's suit to unlock the safe. Open it, and... get ready for a surprise. The back wall of the safe has been blasted open during your fight with Freeze. There is a joker card inside as well as a note wishing you to "Get well soon!". Harley Quinn took it. You have to go retrieve it, as Mister Freeze cannot manufacture any more cure. But Joker has got the steel Mill locked down. Getting in will not be easy. Mister Freeze will help you by giving you the Freeze Blast - its a High Powered sub zero temperature projectile which detonates on impact. Used to solidify water or temporarily incapacitate assailants. You can use the Freeze Blast to block ruptured steam pipes, giving you access to Riddler Trophy locations you did not have access to before.

Your primary objective now is to Retrieve the cure from the joker. To do that, you have to infiltrate the Steel Mill. Leave the GCPD building. A chopper will aim its spotlight on you. But this time its not the TYGER helicopter, its a news helicopter with Vicki Vale in it. Listen to her news broadcast. Suddenly Joker gets on the airwave, and a missile hits the chopper. Your primary goal now is to rescue Vicki Vale from chopper crash site. The location will be added to your map. You want to save Vicki first as she will die if you leave her. So set the objective marker to the reporter's crash site.

The helicopter crashed to the west of the G.C.P.D building. start making your way over there. Vicky Vale will report snipers around her position. Joker wants the reported dead. If you leave her to be taken out by Joker's snipers the mission will fail. Take out the snipers before they kill her. There are two groups of snipers to the east of the crash site, each group is a pair of two snipers. One of them is above the roof of the Dini Towers apartment building to the East. The other group is on the roof of the Kirshen bulding to the Southeast. Approach them from behind and use a surprise attack such as a silent takedown to beat them. After you have defeated all four snipers, grapnel the reporter to safety and talk to her. She does not miss any opportunity to ask for an exlusive interview.

Joker contacts you. Turns out, taking down the chopper was a distraction meant to delay Batman while Harley got back to him with the cure.

Head towards the Steel Mill. There will be lots of snipers on the roof now, so careful not to get in their line of fire. You can see the red lines from their laser pointers to identify their source. You don't have to kill any of them, you can just glide fast and avoid them. It is up to you whether or not you want the extra experience.

Go to the chimney which you used to enter the Steel Mill Last time. But you will realize that you cannot go in the same way this time. The furnace is generating too much heat. You must find another way in.