Sheldon wakes Amy at midnight with his usual blunt precision, announcing, “Happy birthday.” What follows is a perfectly Sheldon-style gift: an “MRI of my brain,” which Amy adores for its strange, deeply personal charm. The moment feels intimate in the odd, affectionate way only these two could manage, and it quickly becomes clear that Sheldon has also been quietly preparing for the annual coitus portion of the celebration. Amy, amused and ready, points out that she did not put on her “plaid PJs” for nothing.