The Doctor waived a quick goodbye to Clara before popping back inside the Tardis. She really had no business jumping into his time stream. It did explain a few things, and he was immeasurably grateful that she saved him, but really the idea of jumping into his time stream was completely nonsensical. She's be okay, though. Well, he thought she'd be okay.
It was oddly quiet in the Tardis, and there was something bothering him.
River.
That infernal woman was getting under his skin from beyond the grave. Again. Even now, he could see her bossing him around, telling him not to leave the parking breaks on. She never really left the Tardis. She'd always be there to him.
Something was really bothering him about her. Of course, he couldn't have saved River Song. He'd barely managed to save her echo to the Library mainframe. But there was something.
"Oh, River," he sighed, eyeing the Tardis controls, "Causing trouble again, are we?" Mainframe. The Library mainframe. It was something.
"C'mon. Think, Rory!" the Doctor said to the empty Tardis. He closed his eyes. Why did everyone always leave? What was it about the mainframe? It was able to hold the human consciousness, so it had to be the most powerful computer ever built, especially since it housed so many.
The Doctor opened his eyes and slapped a hand to his forehead, wide eyed. How could he have been so stupid? He supposed it made sense since he didn't really know River when she died.
But the Library mainframe had to be the most powerful computer ever built, except the most powerful computer in existence wasn't the Library mainframe, it was the Tardis matrix. The Doctor always hated endings anyway.
Quickly, the Doctor flew the Tardis to the largest library in the universe.
Honestly, as the Doctor stepped onto the familiar wooden floors, he wasn't at all sure this would work. He'd landed an hour after his previous incarnation and Donna had left. Hopefully, any lingering Vashta Nerada would still be at bay waiting for the survivors to leave. He'd grabbed a flashlight just to be safe. It wouldn't deter the Vashta Nerada, but it would at least give him warning if they got too close.
He switched in the flashlight and ran to find the central computer. Luckily, after he'd transferred River's echo to the mainframe, he'd left the comm link next to the mainframe console. If he did this right, he'd have a matter of minutes to get back to the Tardis without killing his dead wife. Again.
As he approached the computer console, he noticed two shadows extending from the console pillar. Nothing involving River could ever be easy, could it? He shined his flashlight at the shadow to his left, saw light did penetrate the shadow, and took a few slow steps towards that shadow. As he aimed his sonic screwdriver at the discarded comm link to reverse the data transfer, his flashlight began to flicker. He should've had more time. Looking at the computer screen, he saw the date. Of course. He'd landed a year after Donna and the Tenth Doctor had left. Fantastic.
He seriously did not have enough time for this.
Quickly, River's echo returned to her comm link in the form of a steady blinking light. He grabbed what was left of River and ran.
The way he'd come was hopelessly dark. River's light was still flickering. He simply did not have the time.
The floors around him turned black as the darkness began to close in. He reached for the key at the back of his hair and called the Tardis to him. Clara was going to freak if she ever saw that stunt. Still, it came in handy.
As the Tardis materialized around him, the Doctor rushed River's comm link to the Tardis control panel and resumed the data transfer. This time, River would be home in the Tardis where she should have been in the first place.
The comm link light went out, and the Doctor raced to a monitor to see where River's data was. She was saved very close to the heart of the Tardis, but the old girl wouldn't let anything happen to River.
Bottom line: River Song had been saved. This was a much better ending, because it didn't have to be an ending. Maybe he could save her in a nestine duplicate. Even if he couldn't he would find a way to really save her. There was more time now.
As he started plotting a course for the nestine home world, the Tardis phone rang.
"Hello, you've reached the Doctor," he answered, "Who's this?"
A voice said, "Sherlock Holmes is dead."
The line went dead, and the Doctor stared at the phone. He looked at the date the call had originated from.
"That's not possible," he said.
River was going to have to wait a little longer. The Doctor quickly plotted a course for St. Bart's Hospital and hoped he got there in time.