Dateline: Halloween! It's a classic case of people showing up to a creepy location (in this case, the Arkham Detention Facility for Youth), all thinking the other had invited them. Penguin, Scarecrow, and Mad Hatter, all having had their own problems in their youth are on edge and ready to turn on each other, when they all come to the logical conclusion of who lured them in: Batman.
The three men begin to worry what's in store for the night, but Penguin assures them not to react int he way Batman would expect, that if they stick together, blah blah blah, and a chandelier comes crashing down on their head!
After narrowly avoiding certain head trauma, the three men decide to stick together... elsewhere in the building, seeking shelter. While they walk slowly through the dark halls, they begin to jest with each other about Batman's standard tropes, and Penguin even suggests they should go into business together and open a stained glass repair company.
Being all too familiar with the building, Scarecrow suggests maybe they should head outside, and try and lose Batman in the hedge maze, because that's a brilliant idea, and of course they end up kicking over an old music box that starts to play "Three Blind Mice." Long story short, going outside was a bad idea, as it just freaks them out even more, causing them to run back to the lobby where it all began.
Tensions are high, they all start taking verbal jabs at each other. Scarecrow begins to pull out that reflective thing doctors used to wear on their head, I don't remember what those are called... this leads Penguin to tell him to leave him alone, whip out his umbrella, which breaks open some of Hatter's teabags, and some fear toxin gets throne in the mix, as all three of them start to trip balls.
Familiar with Penguin: Pain and Prejudice? or the first two arcs of this series Hurwitz has written? Well, call back to all those, as we go back to twisted versions of the three men's childhoods, where things are even more messed up due to all the drugs. The three men freak out until sunrise, when they all come to. In an awkward pause, the three bid themselves farewell, and agree never to speak of the night again.
Elsewhere, Bruce Wayne wakes up having spent a rare Halloween night in. Alfred asks if he did any of his usual social calls, but Bruce is honest, he stayed in, as he left the usual riffraff to their own devices... close up, off-brand iPad with invitations to the three men... BAT-TROLLED!