The Botanical Gardens of Arkham Asylum provide fresh greenery as possible rehabilitation for the institution's inmates. It includes a Statue Corridor, an Aviary, and even a top secret Titan Production Facility used by Dr. Penelope Young.
The outside of the Botanical Gardens.
With Arkham East the only part of Arkham Island under control during the early stages of the Joker's takeover of Arkham Island, security guards were posted around and within the Botanical Gardens. While several guards patrolled the outside, one guard was posted at the Glasshouse Entrance, and two others at the entryway to the inner Botanical Gardens. Shortly after armed convicts stormed Arkham East, the gardens fell to them as well. Victor Zsasz raided the Glasshouse Entrance and killed the security guards, arranging them in a lifelike pose around a bench. The Joker's men then entered the inner Gardens, meeting little resistance.
Two Blackgate prisoners armed themselves with security issue weapons and remained at the Glasshouse Entrance. When both Harley Quinn and Doctor Young mentioned a lab for the Titan Project in the Botanical Gardens, Batman decided to investigate, fighting his way through Arkham East and entering the gardens through the Glasshouse Entrance. After defeating the two convicts, Batman used Warden Sharp's Cryptographic Sequencer to bypass a security barrier and enter the inner gardens. Meanwhile, several convicts led personally by the Joker attacked the Flooded Corridor in the gardens. The guards fought back, killing the convicts in the ensuing gunfight, although the Joker managed the defeat them and take security guard Thomas Armbruster hostage.
The Flooded Corridor.
Having bypassed the six armed Blackgate prisoners guarding the Botanical Glasshouse, Batman entered the corridor, eventually demanding that the Joker let Armbruster go. Instead, the Joker pushed the guard into an electrified pool of water, killing him. The Joker taunted Batman with the slowness of his progress, then left, detonating the entrance behind him so Batman would not attempt to follow. The Joker and his men then continued through the Aviary, entering the Titan Production Facility and shooting five asylum security personnel before loading the Titan into oil drums. Batman, meanwhile, had followed the power cables through the Statue Corridor and into the Glasshouse Generator Room, where he hoped to disconnect the power to the Flooded Corridor so as not to suffer Armbruster's fate. Convicts had taken control of the Glasshouse Generator Room, capturing an Arkham janitor, Carl Todd. Batman swiftly defeated them, then used the Cryptographic Sequencer on a control panel set to release Joker Toxins if tampered with. After bypassing the control panel, Batman proceeded back to the Flooded Corridor, finding an alternate way to an Abandoned Corridor through a ventilation shaft. Batman found an alternate route to the other side of the Flooded Corridor, and freed an Arkham worker who claimed to have escaped the Aviary, where the Joker had captured two orderlies from the Titan Production Facility and was suspending them in giant birdcages over a deadly chasm. Batman entered the Aviary, where he found that the Joker did have the two orderlies suspended over a pit inside cages, and was forcing him to play a deadly game. There were four armed thugs patrolling the Aviary and one of them was in a control room with a lever that can drop the cages into the chasm. If any of the Joker's men spotted Batman or if Batman attacks one of them, the thug in the control booth would flip a lever and drop the orderlies to their doom. Batman was forced to rely on all his stealth skills to sneak up to the control room and take the operator out first. After defeating the Joker's men, Batman freed the orderlies from the birdcages, who explained they thought they were working for Dr. Young. One orderly, Robert Stirling, alerted Batman to the fact he knew that there was a secret entrance to the Titan Production Facility. Stirling, however, was not able to tell Batman exactly where in the Aviary the secret entrance was located. Batman followed a trail of Harley Quinn's fingerprints to find the secret entrance, entering the Titan Production Facility via a drawbridge. Here, Batman encountered the Joker and two Blackgate convicts. The Joker, who had perfected the Titan Formula, injected both of the convicts with it, mutating them into mindless monstrosities three times Batman's size and strength. The enraged and mutated henchmen attacked Batman, attempting to strike him with their huge hands and even hurling at him the bodies of fallen security guards killed earlier. While Batman battled the beasts, the Joker took his perfected formula and fled back through the gardens, killing Robert Stirling and the other orderly Batman had rescued earlier in the Aviary. After defeating the two thugs (and wrecking the Titan Production Facility), Batman called upon the Batwing to drop him a Line Launcher, an upgrade to his regular grappling gun. Batman returned to the Flooded Corridor, using his line launcher to cross another chasm to reach another part of the Botanical Gardens. An escaped Poison Ivy awaited him here, having bent the vegetation of the Botanical Gardens to do her will. After Batman threatened her plants, Ivy revealed that an antidote to counter the Joker's Titan drug could be made from the spores of a rare plant growing in Killer Croc's lair under Arkham Asylum in the Intensive Treatment Center. Meanwhile, a group of Blackgate convicts gathered in the Flooded Corridor, denying Batman access.
Batman arrives at the Glasshouse Entrance of the Botanical Gardens.
After Batman defeated them, he continued back through the Abandoned Corridor, and to the other side of the Flooded Corridor, where two convicts had turned the power back on, attempting to trap Batman on the other side of the Flooded Corridor by re-electrifying the water. Batman grappled across the water using his Line Launcher and defeated the Blackgate prisoners. He returned to the Glasshouse entrance after defeating more of the Joker's men in the Botanical Glasshouse. Here, the Joker broadcast triumphantly over Arkham's intercom that he had supplied Poison Ivy with Titan. The plants of the Botanical Gardens mutated and overran the Botanical Gardens, mainly destroying the Garden's facilities. Batman found his exit blocked by the mutant plants, but escaped using an alternate route through the flooring. The remains of the Botanical Gardens soon became filled with Titan Pods which could spit toxic gas orbs at any movement. Batman returned to the Gardens to battle Ivy, who cleared her vegetation out of the way for him to proceed. She allowed him to re-enter the Flooded Corridor, where she unleashed two security guards under her control to attack and weaken Batman. After being forced to defeat the zombified guards, Batman was lured further into the Gardens by the mutated plants. He found Ivy in the Elizabeth Arkham Gardens, where she bounds with a titan plant, controlling the massive plant from inside its mouth behind a shell. She powered toxic vines to grow out of the ground and sent Arkham security guards infected by her mind-controlling spores after Batman, who finally knocked down all the guards and fought off the vines, detonating explosive gel on the mutated plant and defeating Ivy. The ruined Botanical Gardens were reclaimed by the GCPD as they recaptured Arkham Island.