Batman and Robin break in to Arkham Asylum to foil Commissioner Gordon's plans!
This issue takes place after the Millennium #2.
Batman is attacked by Commissioner Gordon, but he's certain that this Gordon is in fact an impostor, and is actually a Manhunter. He gets a tip from a police officer that there is someone in Arkham Asylum, the Floronic Man, who is claiming to be part of the Herupa and Nadia's new millennium. Batman realizes that the Manhunter who is posing as Gordon will try to kill the Floronic Man.
Meanwhile, in Tannersville Robin has tracked down the the Scarecrow. Robin watches as Scarecrow makes up a concentrated batch of fear gas, and while Robin was told not to interact, he breaks the jar containing the gas and exposes Scarecrow to it. The toxin is too powerful, and so Robin takes Scarecrow to the Batcave for Alfred to look after.
That night Batman and Robin pass the guards at Arkham dressed as Scarecrow and Dr. Merula (which Jason chooses because merula migratoria is the scientific classification for a robin). They make it past the inmates by using Scarecrow's fear toxin and fight the imposter Gordon. After he is defeated Batman leaves the Floronic Man in Arkham, and begins the search for the real Jim Gordon, who he tracks to Louisiana.