I don't think there's anything wrong with spoilers in reviews/synopsis, but a warning would be nice.
Here's an example of what I think a good description is:
And here's an example of what I think is really just a spoiler (from Satorare):Sachiko, recently divorced by her husband, has taken her son Masakazu and moved away to start a new life. While looking for a job, she meets Oyama, who arranges for her employment at the local cable TV station at which he works. However the station has entered hard times, and Oyama and his co-workers are fighting to keep up their independent production operations. In order to do so, they have to make a sales quota, and are at their wit's end. Oyama decides he has no choice but to draw his trump card: Shintaro Sakuragai, and ex-caster with a history of scandal. The story which unfolds depicts the trials and travails of the group as they try to keep the station on its feet. --TBS
I just don't think details like the ones in red are necessary to convey the plot. If you think they are, please at least write a warning first!