Amelia Pond had always been one of Clara's closest friends. They grew up together in that little town. Amelia told Clara all about that Raggedy Doctor and his little blue time machine that had a swimming pool and a library.
Amelia wasn't Clara's best friend, but Clara was the only one who would believe her tale about the Doctor and his fish fingers and custard adventure with her. Everyone else said Amelia was being silly or making it up, but Clara believed.
Clara was always there for Amelia, from her night alone in the garden to her wedding night. Clara was the only one who found Amy's parents a little bit strange. Clara was the one who had introduced Amy to Melody. Clara could always rely on her if she needed to be cheered up. Clara and Amy would meet up for tea a few time a years and chat about the good old days of what their lives used to be, and occasionally about the mysterious Raggedy Doctor.
So of course Clara was concerned when Amy went missing. It was strange, how Amy and Rory first disappeared for a while, but Amy did ring Clara up saying they were traveling. Then they returned for a summer, and left with Mels, who was never seen again. The Williams would sometimes disappear for a few days, and it had gotten to the point where no one was concerned when they did. Sometimes a friend of theirs with a bow tie and tweed would show up, but Amy always changed the subject when Clara mentioned him.
It happened one day out of the blue. Clara hadn't talked to Amy in about a years, so she rung her up. Now, Amy always answered her phone, no matter if it was a long conversation that went on for hours or if there was a loud crash and Amy telling Clara she was busy at the moment, and that she would call her back later, and she always did.
Clara tried calling a couple more times, with no success. She then swung 'round by their house to see if anything was wrong. The house was empty and quiet. Their car was stilled parked on the road outside, but the door handle was covered in a layer of dust, and locked.
So Clara knocked on some of the neighbors' doors, and was told they hadn't been seen in weeks. So Clara used a little skill she learned from her dad. She picked the lock.
On the inside, nothing. All the lights were off, which was a bit ominous, since it was getting dark. But in the kitchen, there were two mugs of cold, half-drunk tea sitting on the counter.
Suddenly Clara knew they wouldn't be coming back. She didn't know how or why, but she knew. She knew those mugs of tea would sit on the counter for ages. Tea never finished. She knew that the next time someone comes in the house, they would find it empty. That Amelia and Rory Williams would show up on a missing list. That the house would eventually be foreclosed. Layers of thick dust would settle before an entirely new couple would move in, and the memory of them would be lost forever.
But Clara knew that someone would come by the house eventually, like she did. Someone would be looking for their best friends, or beloved daughter or son.
Clara wrote a note. A simple note to whomever noticed them missing first. To whoever would swing by the house to check up on everything. She simply wrote: "I'm sorry," on a piece of stationary, and left it unsigned on the counter.
Because she knew deep in her heart they would never return, but someone else might need that little apology.
Just then the front door creaked open. In walked a young man with brown floppy hair, an awkward, lanky walk, a red bow tie, tweed, and a deep sadness in his eyes that were too old for his face. He strode into the kitchen, knowing where he was going, and Clara hid swiftly in the pantry.
The man looked tired and lonely and depressed. He first noticed the note Clara had written, since it was a bit out-of-place. He picked it up, and analyzed it. After a moment a few tears overflowed from his eyes as he whispered "So am I."