Wibbledy wobbledy timey wimey, I can’t get enough of this 2-parter! Last week Donna dematerialized in the TARDIS and the Doctor along with archeologist/astronaut River Song and her team were running from two of her possessed crew. The Vashta Nerada, a microscopic alien species that lives in swarms in shadows, but is usually only found in very small, and not dangrous amounts on various planets’ forests, had somehow completely taken over a planet called The Library in the 51st Century. No one had visited it in 100 years, so Mr. Strackman Lux, whose family had built the Library, hired River Song and a crew to investigate. Meanwhile, a little girl in what seems to be modern day England is watching some of this on her tv screens and seeing it in her dreams. Her therapist, Dr. Moon ended last week telling her that what she sees is the real world and her life is the fantasy.

As this week begins, the Doctor and River and her team escape the possessed skeleton-astronaut into a well-lit room. The Doctor is beginning to wonder if he can trust River, who claims to know him intimately, but she gains his trust by whispering a word to him (which we can’t hear). He told her his real name, and decides he can trust her, because he doesn’t tell ANYONE that.

Donna Noble awakes at a hospital of some sort two years after her last experiences in England. The care home is named CAL, just like the computer terminals the Doctor finds in The Library. Doctor Moon, played by Colin Salmon, talks to Donna, reminding her of where she is and she suddenly remembers it just as he’s described. He introduces Donna to Lee, a man with a slight stutter at times. A quick montage shows them in a relationship through getting married to having kids. She seems to wonder what has just happened and Doctor Moon, who visits her, reminds her of the last few years and she calms down and remembers it just so.

The little girl switches her tv from watching Donna to checking on the Doctor with her remote. In The Library, the Doctor is having trouble with his sonic screwdriver, discovering that there is an electromagnetic signal coming from the moon above. Mr. Lux explains that it isn’t a real moon. It’s a manufactured “doctor moon” which acts as a virus checker for The Library’s core computer. River lends the Doctor her upgraded version of his sonic screwdriver which he apparently gave her at some point in her past. The Doctor realizes that when he read on the computer terminal that “4022 saved” didn’t mean Library visitors were rescued, but that they were literally “saved” to the Library’s hard drive. The Library computer systems teleported people but never deposited them. Instead it saved everyone’s patterns to its hard drive.

Just then, the Vashta Nerada spaceman enters the room, but the Doctor stays to talk to it this time. It is able to start using the suit’s communicator system to explain that The Library is their forest. The paper in many of the books was made from trees in one of their forests, filled with Vashta Nerada spores, and they hatched in The Library. River sent “Other” Dave to fetch the Doctor, and eventually the Doctor realizes that he hasn’t just been pleading with the Doctor to leave now, he’s been repeating the exact same phrase again and again. He turns around and realizes Other Dave has also been killed by the Vashta Nerada and his data ghost is echoing through his communicator as it runs out of energy. He finally dashes off. There’s a great beat where the Doctor is beating himself up over what’s happened and River yells at him to focus on who’s still alive and that her Doctor is amazing. He made armies run away and could open the TARDIS with a snap of his fingers.

There’s a great moment where the Doctor gets cornered by the two Vashta Nerada spacemen and says he’s lived this long because he always stands near a door and makes the floor drop open. The spacemen look into the hole to see the door hatch plummet miles down into the sprawling city. The little girl watches this and we see the Doctor climbing hand over hand on the railing beneath the platform high above the city. Awesome!

In the virtual reality world, Donna is watching her children at the playground when she is visited by a woman in a dark veil. It turns out that it is Miss Evangelista, the not-very-bright girl who she befriended. Evangelista explains that her data ghost was saved by The Library’s computer but that she was a corrupted copy and came out disfigured but brilliant - she thinks a decimal point in her IQ got moved. Because of her increased intelligence and inability to interact with anyone, she can see the false reality and is trying to help Donna. She points to the children and we see that they are all copies. Donna gets frustrated and rips off Evangelista’s veil, seeing a terrifying melted face. The little girl sees this on her tv and screams in fear, throwing her remote. This causes one of Donna’s children to fall and hurt their knee. Donna helps the child but her acceptance of reality is shaken.

Later, Donna is confronted with the fact that her family is not real, but the heartache it causes her to think of leaving them is played as a very real and sad moment.

When the little girl hears her father talking to her, she turns him off with the remote, to her horror. She throws the remote down, which activates The Library’s self-destruct mechanism. Dr. Moon tries to calm the girl down but she switches him off, too.

The self-destruct has to be stopped at the computer core, so the Doctor, River, and Lux (the only survivors at this point) make their way down (great special effects of an energy shaft). Lux explains the mystery of CAL. It stands for Charlotte Abigail Lux, his grandfather’s daughter. She was dying and his family built this amazing computer to store her consciousness. She could live forever with all of human knowledge (every book) to pass the time. When the Vashta Nerada hatched and attacked people, she stored 4022 unique brain patterns to save them, but it’s preventing normal operations. The people need to be teleported back to The Library to save her. Because she doesn’t have enough memory to do this alone, the Doctor rigs up a device to allow his own mind to be used as extra computing power. However, this will kill him.

While he builds the machinery, a Vashta Nerada suit confronts him, but he bargains a deal. He will let them keep their “forest” but they need to give him time to get everyone out. At first they refuse, but the Doctor tells them who he is and tells them to look him up in the library archives and they agree to give him one day. River knocks the Doctor out before he can continue. If he died, it would erase all the time they’ve spent together and she refuses to let him rewrite history: “Not one line!” just as his first incarnation once said. River handcuffs him and plugs herself in, saving everyone.

Later, while the survivors teleport home, Donna asks if her husband was real. The Doctor has no way of being sure. Lee sees Donna and tries to call out for her but can’t get over his stutter and is teleported away.

The Doctor places River’s diary and sonic screwdriver on a Library ledge and leaves it, warning Donna that they should not read it because it contains spoilers about their future. He then rushes back, having had a realization. Why, specifically, would he have given River his sonic screwdriver? He pops it open and reveals a dying communicator. Her data ghost has been stored to the screwdriver! The Doctor rushes back to the central core, fighting against time before the communicator runs out of power. At the last moment, he is able to plug it in and upload River to the virtual world, saving her in a sense.

As the Doctor prepares to leave, he decides to test what River said about the future and snaps his fingers. The TARDIS responds, presumably to his telepathic instruction, and does indeed open up. So cool. In the virtual world, River is greeted by Charlotte, Dr. Moon, and the saved data ghosts of the rest of her team. As the show ends, we see that the virtual children and Charlotte live with River.

Pretty damn cool episode. The first one was all about building mind-boggling mysteries and this one propels it forward with action, pathos, drama, and big reveals, twists, and turns. I doubt I could have liked it much more. The only elements that didn’t quite work for me were the possessed suits not being as scary the second time around and in more abundance, and the idea that the virtual world River is uploaded to is so great. It seemed a bit boring, especially for her. I’d love it if she could be downloaded to a cloned body and become a future companion somehow. Or even her past self. Or both. Very awesome episode.

I’d be a jerk to give it less than five out of five sonic screwdrivers: