Batman is sitting alone in his room healing up from his last encounter with Scarecrow, but doesn't have much time, as Crane begins to launch his attack, flooding Gotham with his fear toxin. Bruce quickly heads into the city to deal with the madness, while Alfred, yes, Alfred and Lucius Fox try to synthesize a cure for the virus, but bad news... it would take months to properly create an antidote.
Bruce comes up with an idea though, since he's already fought off Scarecrow's new fear toxin, he figures they can use some of the natural antibodies in his blood to help synthesize the cure... Long story short, Bruce manages to connect his blood stream to some machines in his hovering batplane and uses it to cover the city in a gas made partially out of his blood. Fucking insane and ridiculous? Kind of, yeah. Sort of amazing though? You bet.
Bruce ends up using so much of his blood, that he nearly bleeds himself dry, but makes Damian promise to remote control steer the plane until the job is done. Damian eventually flies his father back to the cave, where Alfred is forced to frantically resuscitate Bruce while giving him a blood transfusion.
Odd scene with Bruce, Damian and Alfred at dinner, the cops finding Scarecrow's hideout with the help of the girl, and a scene of Bruce attending his girlfriend's piano performance later, we find ourselves watching Scarecrow get locked into a cell at Arkham where a hidden vial of his fear toxin breaks, and he's forced to relive his horrors of childhood.