Rachel (Lea Michele) and Finn (Cory Monteith) sing a romantic duet of Room For Two's "Roots Before Branches" in the Glee Season 3 finale. Only problem is, they sing it while Rachel is getting on a train to New York City and leaving Finn behind!
(He's just catching another train a few weeks later, though, right? That has to be it. We refuse to think about the alternative.)