Basically ideas are not "copyrightable," on the expression of ideas is. Even if an idea is repeated, you're not guilty of plagiarism if your presentation is different.
At a tender age, I started constructing a "Sound of Music" knockoff set in France, featuring a prominent family, and a governess for the "six" children in the shadow of World War II. (Prominent families, governesses, and children are recurring themes in literatureliterature.) I was afraid of plagiarizing, but needn't have been, because the "dialog" I produced was neither French nor Sound of Music-like but just "American." In the end, I had the governess marry "Uncle Charles" (not the father), not exactly an original twist, after spending World War II with the Maquis guerrillas (this might actually represent a contribution to literature).
So to answer your question, you won't get sued for following a cut and dried "pattern" that "everyone" has seen before. Just make sure that you are writing with your own "voice," (which, like fingerprints, are distinctive). You probably won't even get sued for inadvertent "copying" if it is limited, accidental, and not a pattern. Real plagiarists fall into a certain "mold." Just make sure that you don't.