That DC would inaugurate its new monthly series of comics featuring Will Eisner's "The Spirit" with a one-shot Batman/Spirit team-up may make marketing sense (even among many American comics readers, Eisner's Sunday supplement hero is more known as a piece of comics history rather than a vibrant character – while everybody knows the Batman), though it's up for grabs whether the end results actually work as a satisfactory introduction to Denny Colt & Friends.
As scripted by Jeph Loeb and penciller Darwyn Cooke (the primary creative force behind DC's upcoming solo Spirit comic), "Crime Convention" centers on a plot cooked up by Spirit nemesis, the perpetually unseen Octopus, to attack a Police Benevolent Association gathering in Hawaii. Lots of Batman and Spirit villains partake in said scheme – with femmes fatale Poison Ivy and P'Gell swapping burgs, locking onto the police commissioners from Central and Gotham City and casting 'em both under their respective spells.
Turns out Commissioners Gordon and Dolan know each other, of course, though neither one apparently has time to read up on the villainesses plaguing each other's city. And so poor Jim Gordon is seduced by that merry black widow P'Gell, while Dolan is sealed with a kiss from Poison Ivy.
Meanwhile, back in their respective cities, Batman and the Spirit have taken note of the sudden migration of every "big-time crook" in their stomping grounds. Separately deducing that this new criminal alliance (which calls itself Friends of the World) is headed toward Hawaii, our heroes show up to try and quash the plan, though in the end it's the criminals' proclivity for double-crossing each other (why anyone would willfully attempt an alliance with the Joker is beyond me) that ultimately does 'em in. As in many of the Eisner "Spirit" stories – particularly the later ones – the heroes exist more to mop up afterwards than to actually prevent a crime from being committed.