It's been a while since I read it, but this is more or less it... Remember that you asked for it....
A woman is suspected of being a black widow killer, as something like three of her wealthy young husbands have died in mysterious accidents. She also has a young son who has lost at least two dads.
Dick wants to investigate, and Bruce points out, apparently to Dick's surprise, that he IS the heir to the Wayne fortune (Be warned, Dick has an IQ roughly equivalent to a cold bowl of chicken soup in this story).
So what does Dick, trained detective, do? Rather than investigate the thing as he has been trained for years, he decides that the only way to find out what's going on is to marry her and see if she tries to kill him.
So he sweeps her off her feet, bonds with her son, and proposes to her. She accepts (It's never addressed, but this woman has some fairly serious "needy" issues IMHO).
Ultimately, on the honeymoon (which Dick spends sleeping on the couch because... well, apparently that would be to icky even for this story), we find out that it's not the wife who is the killer, but the woman we see Roy chatting up, the brides best friend who is consumed with jealousy that her friend wants to spend time with anyone other than her.
After psycho kinda-lesbian bitch is arrested, Dick reveals to his bride that they were never legally married, as he had Babs delay the filing of the marriage licence. He DOES offer to stay with her out of loyalty, and he likes her, but she agrees to do it only if he can promise her that he doesn't have any OTHER secrets. He can't do that so they split.
Where do I begin to say why I think this story REEKS? The whole "Marriage is the only way to do this" assumption is so seriously flawed in the first instance that it boggles the mind. The notion that DICK would come up with such a cold blooded plan, Bruce should have been calling THIS one out of bounds in terms of emotional manipulation. And what Dick does to the kid in question is so OOC as to defy belief. A kid who's lost at least two fathers, is used as a chesspiece by a guy motivated by parental loss? No way.