Disclaimer: I don't own Harry Potter, and only write fanfiction just for fun.
Your heart's desire
"Hermione, look!"
Harry was pointing towards a big mirror. Could it be...The Mirror of Erised? Harry hadn't seen it for years, but he was very sure this was the magical mirror Dumbledore had used to make sure that Quirrel could not get the Philosopher's Stone. The mirror that showed a person his (or her) heart's greatest desire. But what was it doing here in the Room of Requirement?
When Harry had seen the Mirror for the first time, it had showed himself together with his parents. And Ron had seen himself as Head Boy and Quidditch Captain. But Harry had never shown the Mirror to Hermione, who was then at home during the Christmas Holiday.
"Hermione, tell me, what do you see in the Mirror?", asked Harry. Hermione felt slightly annoyed by that question. "Harry, do you really think we have time for a mirror right now?"
"Please, Hermione, could you take a look. Just very quickly." Hermione sighed. "Alright, Harry, if that makes you happy. A quick look, but then we really need to find that Diadem!"
As Harry took his girlfriend's hand, they together looked at the Mirror. Harry was surprised to see that nothing happened. The Mirror only reflected him and Hermione. Could it be this was just an ordinary mirror after all?
Nervously he asked: "Hermione, do you see anything special in the mirror?" Hermione shook her head. "Harry, darling, what are you thinking? What is a mirror supposed to do? Of course I can see you and me and the Room, that's all!"
Harry felt disappointed. For a moment he had hoped that the Mirror of Erised could have helped them finding the Horcrux, just like it had helped with finding the Philosopher's Stone. But apparently he had been wrong. This was just an ordinary mirror. Hermione turned to go, and Harry was about to go with her...as he suddenly noticed the words on the mirror:
Erised stra ehru oyt ube cafru oyt on wohsi.
So he had been right, this was the Mirror of Erised after all. And when he realised the meaning of him and Hermione only seeing each other, he felt his blood getting warmer.
With a smile on his face, he kissed his girlfriend on her cheek and said: "You're right, Hermione. It's just a mirror. Nothing but a waste of time. Let's find that Diadem and put an end to this war."