Some time ago, Joker is being held in Arkham, and during his "therapy" session with a doctor, he offers up his journal (which is incomprehensible) but more on that later... As there's a wedding to plan! Maybe. Joker gleefully skates around the rink, waiting for Batgirl's response to his proposal. Knowing Joker would have no hesitation to kill her mother, Babs begins to play along.
Flash back to the doctor scene... Joker threatens the doctor's young daughter, because, you know... kind of a dick.
With a gun to her mother's head, Babs accept's Joker's proposal, and her new fiancé is just SO relieved. All Babs can think about, aside from the situation at hand, is the fact that her own brother set her up for this. Outside, James Jr. watches with binoculars, and gets a call from Babs' roommate who is hysterical, not knowing what to do, eventually getting James to cave and pick her up.
Back in the past, Joker's meeting with the doctor gets to the point, Joker just wants to talk girls.
Babs is just starting to get more and more pissed, so she throws a hail mary, and calls out to Joker's men she knows to be hiding somewhere, that he's within the kill range of the bomb planted under her mother... and I guess that means bail? I don't know... more on that later. Regardless, Babs takes the opportunity, and lunges as the Joker, beating the shit out of him, specifically targeting his kidney, liver, and oh yeah, spine.
As Joker tries to crawl away, Babs jumps on his back, grabbing his gun, pointing it directly where he shot her, thinking to herself about how long she had thought of this moment, and how despite all the fallout, it would be worth it... then she finds out how loyal Joker's men are, as a sniper fires off a warning shot.
Knowing Joker has her backed into a corner, Babs is forced to play along a little bit more, and before she follows Joker's instructions to where they're to be married, she punches one of his men, puts her mom's finger on ice, and warns Joker that she's not Batman, and the rules don't apply anymore, something Joker is very happy about.
As she leaves, James gives the Joker a call, telling him that he knows the game he's playing, and Batgirl is not his to play with, to which Joker basically says "lol, wut?" to. Not knowing what's going on, Alysia asks what that was all about, as James tells her he guesses that he's about to go help his sister.
Babs then shows up to an old church to find a clown congregation with a priest at gunpoint. The whole story ends on Joker's appointment, worried about infidelity, as he gives a very gory thought on how to prevent it... dismemberment! Yay!