Three teenage girls in an incomplete triangular relation. The base of the triangle is barely there. At the apex is Marie, a serious, short and lean tomboy with a Belmondo-like facial structure. Her best friend is the physical and psychological opposite: coquette, chubby -- I dare say fat -- and desirous for her first kiss with a boy but not quite ready for her first sexual encounter. Because of her chubbiness, boys don't seem interested and it pains her.
The other leg of the apex is a beautiful "fille fatale" blonde vamp. She is deeply involved in the sport of synchronized swimming performing at competitive level. Marie sees her during a competition at the local public swimming pool. Marie insinuates herself into the life of the vamp using the desire to become a synchronized swimmer as an argument. The vamp has a reputation of being a whore, making out with any young male that orbits around her. Marie is not phased out by that reputation. Put a stress on reputation.
The first half is set up. We get to see a lot of synchronized swimming as we become familiar with the three girls. Eventually the narrative leaves synchronized swimming behind and concentrates on the topsy-turvy relations among the three. That's when unexpected things start to happen.
It is a trademark of French films to drop nuggets of wisdom on the viewer. This one is no exception. Here it is about ceilings and the dying. See the film to learn more.
The director says that the use of synchronized swimming is purposeful. That women-only sport is a metaphor for a girl's life: pretty and feminine on the surface while hard working and competitive underneath. A number of scenes drive this point: elegant moves and smiles for the public, legs kicking ungainly underwater. The title in French is also suggestive: "prieuve", or octopus, suggest an individual having to juggle many pressures simultaneously.

I am commenting on this miniseries from the perspective of someone who read the novel first. And from that perspective I can honestly say that while enjoyable, I can see why it hasn't been rebroadcast anytime recently. More specifically, this mini has some serious problems, such as:
1) It is terribly miscast. The actors who played the younger generation were all 15 to 20 years older than the characters. Ali McGraw (45 at the time) was playing Natalie Jastrow who was supposed to be about 26. Jan-Michael Vincent (39 at the time) was playing Byron Henry who was supposed to be about 22. The other Henry children, and Pamela Tudsbury, were also played by actors way too old for characters who were supposed to be in their 20's.
2) Some of the acting was absolutely awful. Ali McGraw at times almost made this mini unwatchable. I have seen more convincing performances in high school plays.
3) The directing was poor. To be fair to Ali McGraw, the bad acting and character development were probably the directing. The portrayal of Hitler was way overdone. His character came off looking and behaving more like a cartoon villain than the charismatic, sometimes charming, but always diabolical genius Herman Wouk painted him as in the novel. Some of the other characters are done so stereotypically (Berel Jastrow) they do not gain the depth of character that Wouk created for them.
4) This mini is very dated. The hokey music, the pretentious narration (it sounded like a junior high school history film narration), and the entire prime-time soap opera feel of the mini made it almost comical at times. Also, too often Byron and Natalie are costumed and made up to look like they are in 1979 rather than 1939.
Someone who watches this without the benefit of reading the novel first will probably not sit through it all, because it will come off more as a late 70's / early 80's "take myself too seriously" prime-time soap drama, rather than the television version of what is certainly a modern American classic.
Remakes of older movies and the like are sometimes poorly done, but this is probably one case where a creative and inspired director could make a very stunning, memorable, and critically acclaimed production. I don't ever see that happening since a remake would have to be just as long (15 hours) or longer to do it right, and given the short attention span of most of the current American viewing public, it wouldn't fly.