Batman Arkham City Walkthrough Part 11 - Meeting Robin

As the assassin fled from the museum in the previous chapter, she left a trail of blood and you hope you can use it to follow her and track down the body of Ra's Al Ghul which has the enzyme Mister Freeze needs to create a cure to the Joker disease.

Scan in the evidence. Your objective will be to Locate Ras Al Ghul and retrieve a sample of his blood. You will radio Oracle and tell her there has been a change of plan, that you are going after the League of Assassins. Penguin had one of the League's assassins imprisoned in the museum. You recognized the insignia. She's a member of Talia's elite guard.

Exit the building. You will request data on the league of assassins and a Line Launcher equipment dropoff. Turn left and follow the trail of blood, in the form of blood splatters on the ground.

It will say "Evidence Identified: Blood Constitution"

Climb to the top of the pole

Keep following the Forensic Trail of the Assassin's Blood  to the roof

Drop down to the ground and keep following the blood trail. Climb onto another roof and go through the gate. Keep following the trail wherever it leads.

Eventually, the Blood Trail has run out. The only way you will find that assassin is to locate more evidence.

Use evidence scanner to scan assassin's bandages for evidence. suddenly you get ambushed.

The only way to find Ra's is to get a tracker on that ninja. Catch assassin and plant tracking device. Once you catch up with her she will attack you. Counter the attack to plant the tracking device. She wont notice. You get pinned down and she says that you only continue to live because the great Ra's Al Ghul allows it.

Suddenly Robin shows up and starts fighting the assassins. You will order him to stand down. The assassins will leave. Robin will tell you that Alfred sent him because he was worried about you.

Give him a diseased blood sample and tell him to get it analyzed and start searching the hospitals and emergency rooms. Anyone with that blood in them will be dead within 24 hours.

Robin gives you the line launcher and leaves. The line launcher allows rapid movement between two horizontal points. Can be redeployed while riding to change direction without touching the ground.

Activate the homing tracker. The homing signal will be in the form of a blinking square with the distance to target. Follow assassin using tracker device to locate Ras al Ghul. The homing tracker will lead you underground. Tell Oracle you are heading underground. Below the surface, Gotham's a maze of old steel and ironwork. Your signal could get weak. Tell oracle to try and stay locked on. She will tell you she is re-routing additional satellite coverage now and wish you good luck. Head through the sewers in the main corridor. You will run onto Joker's henchmen eventually. The will be wearing armor so use Beat Down to take them down.

Joker's got his crew moving through the sewers, hunting down what's left of Penguin's thugs.

Keep following the tunnels. Soon you will reach a gap in the path, use a launcher to slide to the other side, then in the middle of the slide, shoot line launcher towards left tunnel to turn (aka Double Line Launch).

If Batman falls into the water, he will climb out and you will have to try again.

Soon you will run into more thugs. Defeat them and use cryptographic sequencer on the console nearby to open the gate. This leads to the subway.

Keep following the homing signal. Use line launcher to cross through the broken bridge.

Go through the door and enter the collpased streets.