Welcome to Uncle Joker's special party for Batman, everyone's invited, Dick, Jason, Barbara, Tim, Damian, that weird two headed lion cub! All your favorites... only everyone has gags and sacks over their head, and are doused in gasoline... with flints under Bruce's chair. See, Joker want's to talk, but not before serving up the main dish...
To do this, Joker calls on his waiter, who is a very alive, albeit Jokerized Alfred, who on Joker's command, pulls a rope, taking all the sacks off the family's heads, revealing everyone to be bandaged, and bloodied, what's under the serving plates? Why none other but everyone's faces. Why the face removal? Because Joker wanted to show Bruce that beneath his grin, is just his grin. Joker is Joker,
Joker then moves on to ask Bruce a question, why hasn't Bruce done the obvious, why hasn't he killed him? Bruce gives the whole "where does it end" deal, but Joker doesn't buy it, he thinks it's because of their "connection" they have with each other, Bruce "loves" Joker more than the "family," after all he's the only one who understands Joker, as he continuously points out. Joker then pulls out his little book, claiming it to be basically a hit list, or backwards map to get rid of the family. To celebrate the occasion, Joker decides to light the candles, but asks if Bruce will do it, or if he'll have to use the match he just lit.
See, but being that they're in the Batcave systems, Bruce is pretty knowledgable, so he does get up, and boy does it spark a big fire, luckily they're under a water system, and an explosive from Bruce's belt blows the cavern, and puts it out instantly. In the chaos, Joker tries to make his escape, as Bruce goes to free his allies, only to find their faces are perfectly fine. As he unties Dick, he's told to go after Joker, the rest will be taken care of.
Buuuuut, just as Bruce gives chase to Joker, Babs notices something is off with the lion cub, and not long after that, an explosion of Joker gas comes from it's head, and everyone goes nuts trying to kill each other.
Joker comes at Bruce with an axe in the cave, but at one on one, Joker isn't much compared to Bruce, who proclaim's their "dance" to be over, even if Joker has a surprise crowbar or two.
Realizing that it's not going to go physically well for him, Joker tells Bruce about the gas bomb, that they're all going to tear each other apart, but Bruce tells his old foe he has faith in his family, and that they make him stronger, not him (much to Joker's displeasure). Much like a scorned lover, Joker gets pissed, sprays some acid at Bruce's face, and runs again, almost falling off a steep cliff, before Bruce catches him, claiming that everything that happens this night has to be by his hands.
While all this is happening, back at the dinner table, of all people, Alfred starts to break free of the gas and starts to try and break up the fights.
Holding onto Joker, Bruce tells him that their whole game is over, he "broke the spell." He points out where they are, asking if it's where Joker turned back in the cave all those years ago, not because he fell off the boat, but because he didn't want to know, but Bruce knows. He tells Joker he figured it all out, who he is, his history, his family, all of it, and he's about to whisper it into Joker's ear. Joker freaks out, and covers Bruce's mouth with an electric buzzer, causing him to fall off the cliff into the water below.
With Joker gone into the abyss, Bruce picks up his little book only to find nothing in it. Deeper into the cave, Bruce finds Alfred, who successfully reached all of the family, getting the fighting to stop.
Sometime later, Bruce tends to Alfred who is still recovering from the ordeal. He gives Alfred a bell, almost sarcastically. Then Bruce tells Alfred a story he hasn't told anyone... Back after he had taken Dick in, he was on a visit to Arkham. He managed to break away from the group, and make his way into the Joker's cell, where he returned the card that had been left in the cave. Joker turned around silently to look at him, but instead of looking at him, seemingly just looked through him. In an old Morrisonian thought process, Joker truly didn't care who Batman is, it would ruin the fun.
Bruce still feels as if he can't explain that to the family, but also goes on to say that one of the other reasons why he never kills the Joker is that he knows Gotham will just throw something worse at him. Nevertheless, he's invited the whole family over to meet after everything, and expects them soon...
Only no one is coming. Both Tim and Barbara text Bruce, Jason never bothers. Bruce even finds a note from Damian saying he went to train in the downtown bunker. Only Dick is man enough to call Bruce, but also declines. Bruce says he's sorry, to which Dick says he knows. Then Bruce asks what Joker told them all while he was unconscious, but Dick says it doesn't matter, and he'll see him around.
Bruce then walks down to the cave, alone. On the screen, Joker's face remains with an "Identity Unknown" across it. The computer gets done analyzing a minute compound Bruce found in the toxin that was there for no reason. It's the element dubnium, whose old name is hahnium, the original element symbol being...