Ah, so that's what happened. Kinda.
"I'm a patsy!"
The last words of an accused presidential assassin, himself killed - on live TV no less. Ah, the 60s, when America appeared at once to be both starting to "get it" and also coming apart at the seams.
Lee Harvey Oswald was introduced to the world as a lone sharp shooter who felled a president. But, very early in the aftermath, there were doubts and details that, in total, just didn't seem to add up. Accordingly, theories proliferated questioning the veracity of that official position in light of evidence and the interpretations thereof. If the official story is not what happened, is there a plausible scenario that would more reasonably account for all those details, moving us closer to the truth of what may otherwise have actually happened?
And thus, we have Shooter.
No, it is no attempt to flesh out, to the last inch, everything that is or may have been about Oswald. It's a story that has parallels - and even a non-casual mention of/reference to the Kennedy assassination to help us watching at home realize what we were actually watching - a plausible scenario.