After defeating Mister Freeze in the GCPD lab, he begs you to rescue Nora Freeze as she is all what he has left. Even though you two or enemies, you promise him that you will save her. He gives you a Freeze Blast to help you in your mission.

This unlocks the side mission: Heart of Ice

Reunite Freeze with his wife, who has been kidnapped by Joker.
Track down where Joker is holding Freeze's wife and rescue her.

Nora Fries is being held by Joker's men. Mister Freezer managed to track Nora down somewhere in the Industrial District area. If you look at your map you will see a marker for Nora Fries Approx. Location. This will be the whole industrial district perimeter. You need to head there and search for her. She is found in the NW edge of the circle covering the industrial district. From the center of the circle, draw an imaginary line to the NorthWest. You will find Nora in the area on the edge of the line.

Drop down to the boat. Notice the block of wall with the ring on it. Here is where you use your freeze blast grenade. Throw the freeze grenade onto the water, between the boat and the wall. Hop onto the block. Use your batclaw on the ring to pull yourself over to the wall. Use explosive gel to blast a hole in the wall. Enter through the door and you will find yourself in storage warehouse 5B. There are many enemies in the top room. They are equipped with equipment such as shields, body armor, and blades. use tactic such as aerial attacks against those holding shields. Against blade attackers pull away from the attacker and hold counter to perform a blade dodge. If you have the special combo disarm and destroy weapon, use that against the armed assailants. Try also the special combo multi ground takedown.

Nora Freeze is in the displace case in the room. Freeze's wife is now safe. You should tell him. Return to Mister Freeze in GCPD to let him know the location of his wife. Enter the G.C.P.D. building through the East entrance. Find Freeze in the lab. Talk to him to tell him his wife Nora is safe and where to find her, in Warehouse 5B in the Falcone Shipping Yard. He will thank you and apologize for doubting you.

If you go back to the warehouse, you will find Mister Freeze there, admiring his wife. He will thank you again for saving her and promise to help you when you need it.

Side Mission: Heart of Ice
Nora rescued -Case file closed.