Has anyone spilled the plot already?

A faded television actor and his stunt double strive to achieve fame and success in the film industry during the final years of Hollywood's Golden Age in 1969 Los Angeles.

%Leo is at a career crossroads, others are starting (Tate), thriving (McQueen). He is trying to focus on a new outlook.
%Robbie (S.Tate) is attacked near death: falls into coma/fantasy of herself and Hollywood neighbors eliminating the manson family.

"Brad's part looks like the good stuff. While living with Leo on Cielo Drive, he meets Sharon Tate. After she's murdered, he infiltrates the Manson Family."

If that's true, then he's ridiculously miscast and I'm skipping the movie. The "Manson Family" hippies were all very young, teens or early twenties, and they belonged to the hippie culture whose catchphrase was "Never Trust Anyone Over Thirty" (Manson himself excepted, he was early thirties). A man in his mid-fifties would not be able to "infiltrate" such a group at such a time, purely because of his age.

But Pitt gets miscast a lot, because he can get movies financed. Gawd, he's a crap actor and totally unaware of his limitations, which is yet another reason to skip this mess.

Thanks!

The film is mostly fiction, except for the Manson story which gets revised.

Don't read Wikipedia! I'm sure there's more on reddit.