A woman brings sexual assault charges against her molest-y gynecologist, leading to his suicide. That man's wife, who has also recently had a miscarriage, loses her shit, and insinuates herself into the other woman's life by being her nanny, as part of a devious and complex plan to ruin her marriage and turn her children against her.
Manipulation, poor taste and implausibility are often the bedrock of a successful thriller, but The Hand That Rocks The Cradle laid it on a little thick for my tastes. I like that it's trying to push some buttons, which director Curtis Hanson has done effectively in other thrillers like The Bedroom Window and Bad Influence, but if you push too many of my buttons too many times, they start to go numb. This is a movie that exploits for tension such elements as a woman breast feeding another woman's baby, the aforementioned gynecologist rape, miscarriage, an innocent mentally challenged handyman accused of child molestation (played by Ernie Hudson, tragically going full-retard), a villain who verbally abuses children, doubts about the husband's fidelity, children in peril, and many more of your favorite hits. At a certain point enough's enough. It's not that I morally object to any of this (I am the guy who likes Orphan, after all), just that the movie doesn't need to pile it on to such a silly degree. It's a strict adherent to Murphy's Law of Thrillers: everything that can go wrong, will go wrong, exactly when the screenplay requires it.
On the other hand, never let it be said that Hanson isn't a solid craftsman. In addition to an effective suspense scene or two, I couldn't help but admire the efficiency of the film. There's not an ounce of fat, no unnecessary details. Every innocuous thing that happens, from a character having an inhaler, to a character smoking, to an alarm clock playing classical music... it's all some sort of set up for a plot point or or suspense sequence that will pay off later. In that sense, you could say I enjoyed the movie, my enjoyment only matched by how much I disliked it.