Elrond is distressed about the Numenorean fleet sailing to Valinor and doubly so about the fact that Sauron seems to be behind it all. Fortunately, Maglor is available and despite the fact that he couldn't give two shits about stupid Numenoreans challenging the gods, he's willing to help. Provided that a bit of backstory gets told, of course. Perhaps it's time to reveal a rather important secret to Elrond?
(One of my stories from the Seven Stones for Seven Sons collection on AO3.)