The Joker, Vol. 1

The Joker steals a new fear gas developed by S.T.A.R. Labs and ends up competing with the Scarecrow to see whose fear-weapon is the mightier. Joker continues his normal crimes using the new fear-gas and he attempts to steal the painting of a hyena from a public park when his plan is disrupted by Scarecrow, who has developed a stronger version of his fear toxin.

In the confrontation, Joker is able to resist Scarecrow's toxin thanks to nose filters he had previously equipped. Desperate, Scarecrow tries to use the STAR Lab fear gas, but learns too late that Joker had replaced it with a variation of his own Joker Venom which only causes uncontrolable laughter, incapacitating Scarecrow. By the time the police arrive, Joker makes his getaway, while Scarecrow is taken by the authorities.

Joker decides to return to Arkham Asylum through his secret conection between the Ha-Hacienda and the mental hospital in order to stop the police from chasing him.