Batman Prelude to the Wedding Harley Vs Joker (2018) #1

Harley Quinn knows a thing or two about dysfunctional relationships. When she hears that her old flame is trying to get in the way of a happy new life for one of her best friends, the Maid of Mischief tracks The Joker down to give him a piece of her mind - and maybe a few blows from her hammer, too.