As you wander into the collapsed streets, Batman suddenly does not feel well.

Oracle contacts you "Are you alright? Did something happen? All the readings from your suit just went red."

Joker's disease is starting to show its signs on Batman who is beginning to get weak. You must find a cure soon.

You will soon reach a big gap. Use line launcher to slide to the other side. There will be a security console marked with a red lock. However, that panel is protected using TYGER encryption protocols. You can't decrypt it without access to the Master Control Program Strange uses.

Go defeat the thugs that are standing around the corner It looks like Joker is sending his crew down to steal weapons off the TYGER guards.

Go through a door to reach  a big chamber. Thugs are holding Fiona Wilson hostage. Be careful as they are heavily armed. When Batman tries to activate detective mode, it fails. Someone in this room is using a signal jammer. You need to neutralize him so that you can scan the room for targets. Neutralize the Signal Jammer Thug to unscramble detective mode. After you've neutralized him, start taking the thugs down one by one. Use Inverted takedowns when possible. Grapnel onto the gargoyles to quickly move between vantage points when you are spotted.

One of the thugs will take the hostage. Use detective mode to locate hostage. Take down the hostage taker without being spotted. Approach him from the back when he is not looking and disable him. Finish off all of the thugs and rescue the nurse.

You will contact Oracle and tell her that Joker's not stealing the weapons from strange. Strange is giving Joker the weapons.

Head down to the ground floor and towards the door with the sign that says "Wonder City" on the top. Enter the Wonder City.

You know enter Wonder Avenue. Batman Collapses. The disease from Joker is running its toll. He coughs blood. But he manages to get up and continue on the quest.

You will reach a big door that says "Welcome to Wonder City". Use REC gun on the motor beneath it to lift the gate. Behind the door a thug will collapse, stabbed. Who killed him? Look up. There are more bodies hanging from the wall.

Use your electrical gun to open the 2nd gate.

Approach the third door. Suddenly 3 ninjas appear! Ninjas can attack with multiple swipes of their sword in a short space of time. Use the blade dodge to avoid these attacks. Perform the blade dodge takedown by releasing the counter button between each of the attacker's multiple swipes. Once you've defeated the three ninjas, approach the next door. There will be a panel blocking the gate's motor. Use explosive gel to get rid of it and use elecronic gun to open the gate.

Pass through the door and head down the corridor towards the next door, the one with the sign that says "Temple of Wonder City".

The announcer says: Mechanical Guardians will serve you, watch over you, and when necessary, protect you from the worst of Mankind's sins.

Reach the Wonder City Temple Door. The tracker's signal continues beyond this door, but the door looks like it's been sealed for decades. The assassins must be using another way to get through. Scan and analyze the mechanical guardians to see how the assassins entered the temple. Reconstruct video data from the mechanical guardian. It will say "Analyzing Physical Encoding" and then "Receiving Data" and "Connection Closed - Incomplete Data".  Locate more mechanical guardians to fully reconstruct the data. You have to scan seven mechanical guardians to get the complete video. Some notable locations: one of them is SE on a high ledge, another one is a displace case, and another one is in a small area above the door. After you scan three of them you will be attacked by Ninjas so prepare to fight. Then finish scanning the rest of the guardians. You will be attacked by yet a couple of more ninjas after downloading data from the fifth mechanical guardian.

The assembled surveillance footage will then show you where the assassin went.  Locate the secret entrance using the video data. Watch the video and find the secret entrance the assassin used. It will be to the left of the temple door, near some posters. Activate secret panel to go through. It will look like a sword fits there. A ninja will attack you. Grab her and use her sword to open the panel.