Certain genres, such as mysteries, thrillers, and science fiction, place particular emphasis on plot. New writers are often encouraged to write detailed plot outlines (just about as often as they are advised to ignore plot outlines and just write, letting the story evolve organically). In the end, each writer must find their own approach.
However, if you feel yourself drawn to plot outlines, this warning is for you. The only writings that rest entirely on plot are the riddles you learned in preschool and those story problems in you middle school math books. Beyond these all story telling hinge on characters, characters and characters. Even novels with complex plots (Dickens, Delinsky, Christie, Grisham, Patterson immediately come to mind), the characters drive the story.
The risk of a plot outline is that the author forces the characters to behave as the plot demands instead of visa versa. As a story unfolds, the primary questions in the author's mind should be what will the character do next? Even when the reader imagines they are reading to find what happens next, they are really want to know what the characters will do and what will happen to them.
Never let the plotting drive the characters actions.