"I'm always running to the place where something bad just happened," narrates Porter Wren (Adrien Brody) at the beginning of Manhattan Night, which explains his presence in this faux noir. Porter is a columnist for a New York periodical; “I used to think that my stories could make a difference. Now I just hope they are enough to feed my family.”
Unless they actually eat the newspaper after reading it, I highly doubt that a meager column could support a family of four — or, for that matter, a single person (unless that person is J.J. Hunsecker, and Porter most certainly isn’t). Thus, when Porter calls his Manhattan home a "miracle," the only miraculous thing about it is that he can afford it on a columnist's salary.
Although his surgeon wife Lisa (Jennifer Beals) is presumably the one paying the bills so he can play journalist, Porter has no problem cheating on her with socialite Caroline Crowley (Yvonne Strahovski), widow of Simon Crowley (Campbell Scott), a famous film director/enfant terrible whose corpse, or what was left of it, is found in the ruins of a demolished building.
Caroline asks Porter to investigate Simon's death, which is pretty stupid considering that a) she was there when it happened and not just as an innocent bystander, which of course means that b) any information Porter digs up can be used to incriminate her, something he actually threatens her with at the end.
The only possible motive for Caroline's behavior is that she wanted an opportunity to seduce Porter, but he is so dazzled by her and her lifestyle — "I just went up in the elevator with Leonardo DiCaprio," she tells Caroline in one of his visits to her apartment; unfortunately Leo got off at another floor (where a much better movie was presumably being filmed) —, that Caroline only had to ask 'voulez-vous coucher avec moi?' to get in his pants. In fact, Porter's infatuation is such that needs no more motivation to call her than a Bazooka joke comic — though God knows he wasn't going to find it in the script.