The action takes place in the 1860s. The main heroes are Ben Cartwright (Lorne Greene) and his three sons - the eldest, Adam (Pernell Roberts), Hoss (Dan Blocker) and the youngest Little Joe (Michael Landon). They live in the Ponderosa ranch in Nevada (map published). What they mainly do is shoot villains, visit the saloon in Virginia City, deal with problems and do everything the sheriff should, but doesn't.
The best thing (for me) is that from this point of view it sounds dead boring, but watching one single episode will immediately stop these crazy thoughts.
PS RIP all the actors. Pernell Roberts died of cancer January this year and was the last member of the cast.