On a routine trip returning The Joker to Arkham Asylum, the Batman himself must deal with traps set within its inner sanctums, purposely set by the now escaped Joker, along with the rest of his rogues' gallery that are now free within the premises.
Welcome to the madhouse
Did You Know?
at one point, a security guard angrily tells Joker as he's being taken back to Arkham that he'll pay for the deaths of three of his friends from the previous escape, only for Joker to be shocked that he only managed to kill three, and state that he'll try to improve by killing 100 more people the next time he escapes. By the time of the end of the game, he did kill well over 100 people at Arkham. See more
At the beginning Harley Quinn set charges to an elevator and causes it to crash down while being pulled up by the counter weight.
If the elevator cables were cut (as they clearly were) the elevator comes down, but so should also the counter weight. See more
All units proceed to Gotham City Hall. The Joker has been apprehended. Batman is now en route to Arkham Island.
Followed by Batman: Arkham City