Fulcrum (Harry Potter/BBC Merlin Xover)
There are some things that are just not supposed to happen, some wrongs which should not occur--these are the things Merlin knows he and Arthur were brought into existence to prevent. Then of course there are also certain things that would make everything better if they happened, and folly or stupidity has stopped them from occurring--Merlin likes to put these back on track as well. Arthur calls that part meddling. Harry Potter finds himself in the middle of both.
AU from the scene on the Astronomy Tower at the end of Half Blood Prince, and leaving out the unsatisfactory ending for BBC Merlin as well.
Rated Mature for sexual content in later chapters (not violence).