Long live the King, the Priestess and the Warlock (слэш)

After Arthur died from his wounds at Camlann, Merlin sends his soul back into his own body in the past, where he's still Prince, Morgana isn't crazy- yet- and he hasn't married Gwen.
After Morgana returns with plans to overthrow Uther, Arthur decides to intercept her, hoping that by talking to her before she does anything irreparably drastic, he may be able to salvage their relationship and stop her from waging war. An unexpected side affect of that is that Merlin realizes that Arthur, acting very Kingly, is suddenly very Attractive.
Continuation of The King is dead, long live the Prince. Can be read as a stand alone.