When: Season 5

The product of the full McNulty, the fake serial killer is the closest thing the fifth season has to a main plot, mocking the “one last job” cliché by putting all of the cops back together on a topsy-turvy version of a major case. After creating a fictional serial killer to prey on the homeless in order to get money for real work, McNulty essentially becomes the commissioner of his own private police department, a hypothetical that doesn’t work as well as “what if a cop tried to legalize drugs.” Admittedly, the success of the ruse is about as plausible as Hamsterdam, but this one doesn’t dig nearly as deep into the possible consequences of everyone’s actions, or make a larger thematic point. Mostly, the story is about

McNulty and Lester (and Kima, who has to choose to rat them out).
It’s a way of pulling in all sorts of other things, too; material that pushes the boundaries between dark comedy and outright satire (think of the FBI agent who makes a big deal out of his media appearances and consulting for CSI). The interesting stuff here is all reactions from characters we already know, but The Wire was never really a character study so much as an institutional one. Worst of all, we barely even see Lester’s case against Marlo, the justification for the entire scheme.