-Dead Man's Point-
Hulk and Batman make it to a large cliff, and after a series of incredible acrobatic stunts from the two heroes, they make it to the entrance to the concealed Batcave, which scan the two's biometric signatures before letting them in.
"Identity confirmed. Disabling countermeasures. Security deactivated." A computerized voice says as Hulk and Batman enter, the door shutting behind them as they walk deeper into the cave. Hulk and Batman walk towards a large set of monitors as Batman sits in a rolling chair and begins working while Hulk sits on some reinforced steel boxes, looking down as if something was bothering him.
"Dr. Young was heading up a project. It was big, with lots of funding. Here are the last notes she filed. I can't make sense of it; what does it mean?" Oracle says into Batman's earpiece as he looks through Dr. Young's notes on the computer.
"Hmmm...looks like she was experimenting on the Arkham patients. This new chemical barely resembles the original Venom compound." Batman replies as he compares samples of the Venom drug and the new drug Bane was injected with, noticing severe differences. "There are a number of changes that appear to amplify the strength of the drug. Multiple references to a Titan formula. Even a small amount could trigger a transformation in the host, eliminating the need for that cumbersome storage tank that Bane required." He adds.
"Sounds like Joker was planning something with Bane. Too bad he's already been dealt with..." Hulk says, still looking down at the floor.
"Hang on." Batman says. "These notes...they aren't complete. The formula is missing. That must be the secret Dr. Young is hiding from Joker. If Joker gets his hands on this, he will create an army of a thousand Banes."
"My God...! Is Joker crazy enough to do that? Ugh, what am I saying? You guys have got to stop him!" Oracle says, realizing the seriousness of the situation.
Batman turns around and looks at Hulk, noticing how sad he looks. "Hulk. What's wrong?" He kneels down in front of the large creature.
"I...I miss Diana." Hulk says with obvious loneliness in his voice. Wonder Woman was the one woman he ever loved, and he missed her like crazy. "I wish she was here with us, Bat..."
"Me too, Hulk. But right now, we have to stop Joker from getting his hands on the Titan formula...or Gotham will be destroyed. Okay?" Batman says, to which Hulk nods as he stands up, ready for action as Batman contacts Oracle. "Oracle, we're going after her. Dr. Young was heading to the Mansion with Cash. We'll get to the surface via the catacombs.
-Later-
Sewers
After dealing with some thugs, Hulk and Batman head for a reinforced door, only to be jumpscared by Killer Croc on the other side, who punches the window in a failed attempt to escape.
"I will find you...rip your flesh like paper...!" Croc snarls to them before leaving.
"Hmm...sounds like he really wants us dead." Hulk says in response.
"No doubt. But he's trapped. He can't hurt us." Batman says as the two continue to walk through the sewers.
"I've been digging deeper into Dr. Young and what she's been doing. According to her bank records, there have been multiple payments, starting last April until 2 months ago. Then...nothing." Oracle says. "The payments came from a company owned by a Mr. Jack White."
"One of Joker's oldest aliases. So...Joker pays Dr. Young to create his army and then all of a sudden, he stops? Doesn't make any sense..." Batman says into his comm unit before ending the call.
"Hmm...maybe she did something he didn't like and stopped paying her because he was angry?" Hulk theorizes. "That's what I would do...if I had the patience."
"Hmm. You may have a point, Hulk." Batman says as he approaches a door very similar to the one Croc tried to break down earlier.
-Main Sewer Junction-
Hulk and Batman walk into an elaborate sedtion of the sewer that was filled with several collapsing structures of brick and stone. It looked like they'd collapse at any moment.
Oracle calls up Batman again. "Hey. This is weird. The payments to Dr. Young's account didn't stop exactly, they were declined. Dr. Young put a block on her account. Smart."
"Hm. Sounds like she had a change of heart. She tried to block the payments. Joker doesn't like it when his partners try to back out."
"So he decided to get himself back to Arkham, find the formula and create the army himself!" Oracle says with shock in her voice.
"Exactly..." Batman says, ending the call. He tries using his Grapnel Gun to get to a higher platform, but the bricks give way. "The structures are too decayed. Looks like I'm getting up there the old way.." He says, forgetting about the fact that Hulk could get him up there much faster.
"Ha. Who needs that when you got me?" Hulk boasts as he grabs Batman and jumps upwards, landing on the structure that Batman was trying to get to.
Oracle calls Batman again. "I've hacked into her email accounts. Two mails stand out. The first is a resignation ketter, dated last week. Sounds like she was trying to get away."
"The second one?" Batman asks, getting the feeling that the second mail was going to be disturbing in some capacity.
"A message from Joker-Well, Jack White. It's a long thread. She's begging to stop the experiment, says it's too dangerous. He's not listening...Let's see. Random threats to her family, couple of bad jokes...Oh. How charming. A picture of a dead baby and a threat!"
"Go on.."
"He says, 'I'm coming for you! I want what I paid for!' Then another joke about wheelchairs...and a drawing of some kind of donkey." Oracle adds.
"A...donkey?" Hulk asks, puzzled by Joker's scare tactics.
"No mystery why she's so scared. We're coming up to the surface. We'll find her." Batman says as he ends the call.
-Arkham Mansion-
Main Hall
Batman and Hulk covertly enter the Mansion, though Hulk had to turn back into his human form in order to fit through the tight fitting air vent. Upon landing, Batman and Bruce spot a large group of thugs, no doubt some of Joker's men as Joker's voice came on a loudspeaker.
"Joker here with a little update for you all. First, the good news. We have Dr. Young. Bad news is she's not talking. She's hidden a document somewhere in here, and I want it found! I've got a plan...or six, to loosen her tongue. But in the meantime, search every kook and granny. There's a prize for whoever finds them." Joker says before signing off.
"That's nook and cranny, you idiot." Bruce thinks to himself in response to Joker's words.
"We have to find those notes before Joker does." Batman says as he leaps down and easily neats the henchmen down in a brief brawl.
-Later-
Bruce stays behind while Batman continues on to search the mansion for Dr. Young's notes as well as the doctor herself. Bruce didn't know what was waiting for them, and he still needed to rest after his brutal fight with Bane. Batman comes across a doctor and an Arkham guard tied to a an oversized box that was wrapped ip like a Christmas present. After swiftly navigating the air ducts to reach them, Batman saves the two men.
"You're safe now. What happened?" Batman asks as the men try to collect themselves following their ordeal.
"It-It all happened so fast. Some patients broke in, began tearing up the place. Like they were...looking for something. Bill here fought back, but there were too many! They took Dr. Young. She ran in here and they followed!" The doctor says.
"I'm sorry. When I came to, we were all tied up. Doc Young was gone..." The Arkham guard, Bill said sadly. It was as if he was blaming himself for Dr. Young's abduction.
-West Wing Corridor-
Bruce stumbles into a little trouble. As he began aimlessly wandering the mansion, an inmate holds him at gunpoint, the barrel of the automatic rifle aimed at the back of his head. He simply grins as his eyes turn green. That goon just sealed his fate...
Elsewhere in the corridor, Batman comes across a Joker goon holding a couple of Arkham guards at gunpoint. He sneaks up on the thug and takes him out silently. After this happens, the collar around the goon's neck starts beeping and emitting a laughter-like sound.
"What's that collar doing? Why's it making that noise?" Batman asks.
"It's a suicide collar...but it sounds weird." One of the guards says.
"Suicide collar?" Batman repeats.
"They've got some other names, but, well, we use them to monitor a patient's heartbeat. If it drops too low, the alarm goes off and a crash team rushes in." The guard explains more as Joker is seen on a monitor.
"And so does my crew if you trigger one. How do you like them apples, Bats? Standing around in the...hmm, let's see. Ah, the west wing. My men would be there now if they weren't a busy knocking a little sense into Cash. Tell you what. I won't spoil the surprise and let them know you're coming." Joker says before cutting the feed.
-Later-
Mail Room
Batman enters a mailroom, overhearing several Joker thugs interrogating Aaron Cash as well as another Arkham guard, who refuses to tell them where Dr. Young is hiding. After taking down the thugs down, he unties Cash and the guard.
"Thanks." Cash says in a minorly sarcastic tone. He always sounded like that.
"Where did Dr. Young go?" Batman asks, getting right to the point.
"I told her to run. These guys came in looking for her. I told her to go to her office and hide." Cash answers.
"Does she keep her records there?" Batman asks.
"I guess. She was pretty desperate to get in there. Her office is over there!" Cash says as he 'points' in the general direction of her office.
"How long ago was this? I need to find her notes before Joker gets his hands on them!"
20 minutes. Maybe more. What's so important about the notes?" Cash asks.
"Joker wants them. That makes them important. Stay here; I'm going to find her." Batman says in answer as he leaves.
-North Corridor-
As Batman wanders through a corridor, Joker comes on a loudspeaker. "Going after the notes yourself, eh, Bats? Good luck! I've got a crew working over the doctor as we speak. They'll squeeze the formula out of her soon enough. Why don't you just give up? Go on, roll over and die for once! Be your best friend...!" Joker teases.
-Dr. Young's Office-
Batman enters Dr. Young's office through an air vent and begins searching for clues that'll reveal where she is. He notices a safe that has been opened.
"Someone has already got to the safe! The only question now is who opened it?" Batman asks himself as he looks at the door leading into the office. "No sign of forced entry. Whoever opened it knew the combination. Hmmm." He wonders aloud as he watches surveillance footage on Dr. Young's computer, showing her opening the safe. "Good. Dr. Young got to her notes before Joker. She's taken them to hide somewhere. I need to follow her and find out where she put them." Batman scans her handprint on the safe before contacting Oracle. "Oracle, I'm on Dr. Young's trail. I've had to calibrate the scanner to only show recent prints. If I follow these, I will find her or the notes."
"I hope it works. Just so you know, the GCPD found one of Joker's bombs downtown. It was full of marzipan and kittens." Oracle comments.
"As I thought. It's just a twisted diversion. The real action's on Arkham!" Batman says, knowing the bomb threat was a farce all along.
-Library-
Batman returns to the ransacked library, noticing a slip of paper sticking out of one of the many oversized books. He pulls it out, realizing it's Dr. Young's notes for the Titan formula.
"Oracle, I found Dr. Young's formula." He says as he sprays his Explosive Gel onto it, causing it to slowly burn away to ash.
"Great! So does that mean you've stopped Joker?"
"It's never this simple with him..." Batman says. Moments later, Joker can be heard on the loudspeaker.
"What's that you've got there, Bats? No! Not the formula. What am I going to do? Who can help me now?" Joker asks in mock despair. "What's that? How about our old friend Zsasz? Hmmm, I did bump into him on the way back from the Gardens, where no doubt he was acting out some twisted fantasy. Maybe he could get her talking? I think he probably can. Great plan, Bats."
As Batman leaves, a familiar gas is sprayed through the room's vents.
-Later-
Batman walks through a long corridor when it starts raining...indoors. Something was wrong. It got stranger when he started to hear his parents' voices. "I can't believe you insisted on sitting through that movie again, Bruce. Come on. We'll be late for Alfred."
"I'm sorry, Daddy." The voice of a much younger Bruce said.
"Go easy on him, Tom. He loved it so. Alfred will wait. Keep up, Bruce!" The voice of Bruce's mother called out to him. As Batman walked further down the hallway, which never seemed to end, it started to warp as if it was changing into a different location. "Where are you taking us?" The voice of Bruce's mother asks.
"We can cut through here." Bruce's father says in answer.
"But it's starting to rain. Bruce is tired. Can't we just wait for him here?"
"Come on. Keep up. We're nearly there." Bruce's father says as the hallway was now a dark alley. Batman now realized what was going on. Scarecrow's Fear Toxin was affecting him again. Soon, the voice of the man who killed his parents could be heard.
"Oh, God!" Bruce's mother exclaims.
"Please! There's no need for this!"
"Stay where you are; I'll shoot!" The man says as the hammer of a handgun clicking could be heard.
"I'll give you whatever you want-" Thomas Wayne begins to say, only for the man to shoot him.
"Daddy!" Young Bruce cries out.
"Tom! Oh, God, oh, God. Tom!"
"Be quiet, lady. Just shut up. Give me those pearls."
"Stay away from me! Run, Bruce!" Martha Wayne beckons before another gunshot is heard.
"MOMMY!" Young Bruce cries out. The scene suddenly changes, as Batman stands over his dead parents and mourns them before entering a warped version of the Arkham Mansion's main hall as he sneaks past the giant Scarecrow again, this time having to contend with skeletons that Scarecrow creates. After dealing with the skeletons, Batman finds a Bat Signal and shines it on Scarecrow like before, releasing him from the reality warping effects of the toxin.
-Clock Tower-
Batman sees that he somehow made his way to the clocktower while under the influence of Scarecrow's Fear Toxin. Realizing he had no other way out, he cuts the steel cable holding the bell, causing it to crash onto the floor below, making a path for him.
After wandering for a bit, Joker appears on a monitor. "I've been waiting for you, listening to Zsasz make the good doctor scream while you played around in Scarecrow's world. How was it this time? Learn anything about yourself? Oh, tell me. Pull up a seat. Talk to me! I'm all ears...Actually, that reminds me. I could've sworn I heard Zsasz cutting her ears off. Certainly sounded like it. Hahahahaha!"
-Warden's Office-
Batman spots Zsasz dragging Dr. Young away, his knife dangerously close to her face. "Stay where you are, Batman! Listen to me carefully."
"Help me! Please, somebody help me!" Dr. Young pleads hysterically.
"Come any closer...and I'll paint the walls crimson with her blood!" Zsasz says threateningly as he moves the knife closer to his hostage's head. Not wasting another second, Batman flings a batarang at Zsasz, hitting him directly in the face, knocking him out cold. As Barman walks towards him, Dr. Young starts pounding her fists on Zsasz's chest in anger.
"You monster! You evil, evil, evil monster!" She wails as she keeps hitting her unconscious attacker.
"He's not going anywhere. You can stop now." Batman says as he helps the traumatized woman stand up.
"Sorry...I'm so sorry!" She softly says.
"I saw Bane." He says.
"I know, I...Joker threatened me. I wanted to stop the experiment. I tried to give him his money back."
"Joker doesn't take no for an answer." Batman says.
"He wants an army. A horrible, twisted force to destroy Gotham, but he couldn't do it without the formula. I hid it, but..." Dr. Young stutters.
"Now he has Venom, and your formula." Batman says, finishing her sentence.
"God. He has gallons of the stuff. There's a lab, hidden in the Gardens. It's locked off, but the security key codes for the entire island are in the Warden's safe!" Dr. Young says as she approaches a safe built into a wall.
"What else is Joker planning?" Batman asks as Dr. Young moves a plague from the wall, revealing the safe.
"How should I know? You think anything he says makes sense? I think he's insane..." She says, getting jumpscared by a silly face drawn on the safe. "Oh, my God!"
"GET OUT OF THE WAY!" Batman yells out. But it's too late, as a massive explosion erupts, causing both Dr. Young and Batman to fly backwards.