Our Doctor Who superfan Lizo reviews the eighth episode of the fourth series - Silence in the Library.
The Doctor and Donna land in the biggest library in the universe - so large it fills an entire planet.
It's also a place where something terrible happened in the past, and it's now completely deserted.
That is until a team of explorers arrive. And soon they're all in danger, because there's something lurking in the shadows.
This is easily the best episode so far this series.
It does the same thing as many Doctor Who stories, by taking something very ordinary, and making it terrifying.
Eve Newton is brilliant as the Girl
Last year, this was done fabulously well with the scary statues in Blink. And this comes from the same writer, Steve Moffat, who's also soon to take over as the head writer of the show. So fans should be happy that the programme's in safe hands.
In many ways, this is even better than Blink, because the story has more layers to it.
There's not only the threat in the shadows, but there's also the Doctor's mysterious connection to one of the explorers.
As well as a storyline about an ordinary girl who somehow is dreaming about events happening in the library.
Something in the shadows puts the explorers in danger
There are some great performances too. Eve Newton is superb as the Girl, as is Alex Kingston as Professor River Song.
And Talulah Riley is fantastic as the not too bright Miss Evangelista - she'd make a wonderful and very different companion to the Doctor.
But the real star of this episode is the writing. Steven Moffat has cleverly put together an episode that fits together like a jigsaw, lots of things don't yet make sense, but we know they will when we can finally see the whole picture.
He knows how to keep the pacing just right too.
It starts off creepy and intriguing. By the end it had me huddled on my sofa with my hands over my mouth in terror.
But there's some humour too, just the right amount to release the tension that builds up slowly in waves throughout.
It's a two-part story, so lots of things are left unexplained by the end.
So the huge challenge is to make the second part, Forest of the Dead, as good as the first. Because Silence in the Library is just about as good as Doctor Who gets.
Five out of five
Unfortunately this review is now closed but there are reviews on the main review index.
"I really enjoyed the episode. It reminds me of the older Doctor Who, like Remembrance of the Daleks."
Andrew, 14, London, England
"I think that was the worst episode ever and I love Doctor Who."
Lewis, 9, Dublin, Ireland
"I thought the story was very gripping from start to finish. I was especially shocked and amazed when Donna's face appeared on the library assistant."
Omid, 12, Dubai
"I normally love Doctor Who - the empty child was so scary! But it's not really as scary now. I hate being scared, but for Doctor Who I made an exception. But it's just kind of boring now, like it's made for younger kids..."
Jelly, 13, London, England
"The best so far. I wonder who that lady is and also what happened to Donna? I can't wait to watch the next episode."
Callum, 10, Hampshire, England
"Unbelievable. Moffat has done it again and created the finest episode of series four (other than perhaps Planet of the Ood). One of the best episodes yet. 10/10."
Adam, 11, Swansea, Wales
"I think this episode was brilliant and the scariest of the series by far! Steven Moffat's episodes are always the scary ones!"
Lauren, 10, South Glamorgan, Wales
"Amazing. As always, Steven Moffatt did not disappoint! He is my fave writer for Doctor Who and I can't wait for him to become executive producer! And the thing that happened to Donna, that was really cool! Maybe you can't leave the library without becoming a node? And Riversong - that's a great mystery. Maybe she's the Doctor's future wife???? Best episode ever and that Doctor Moon is creepy! Great acting, great plot, spooky monsters! Love it!! "
Deanna, 13, Amersham, England
"I thought it was an amazing episode with so many twists and turns! I'm unsure what the connection is between the doctor and the woman, but I have a feeling it might be Jenny."
Wez, 13, Warwick, England
"I think this was a sad episode because every one thinks Donna has died but i think in the next couple of episodes Donna will be in them because it can't be the end of Donna. This episode was a little creepy with the shadows."
Sarah, 12, Port Talbot, England
"I thought that this episode was the worst of series four! In fact the worst episode EVER! The plot was all over. The characters were dull and had no contrast, the scenes used for the episode were the same for the whole thing, which made me lose concentration... Just overall extremely disappointing!"
George, 13, Boston, England
"Donna!!!! I couldn't believe that one. That was quite possibly one of the best series 4 episodes. I am so glad Steven Moffat is taking over, the show is in safe hands. I will now always double-check how many shadows I have."
David, 13, Edinburgh, Scotland
"This episode was brilliant! I was so caught up in the story that before I knew it, it was over. One of the best episodes ever! I cant wait until next week!!!"
Amy, 12, Wirral, England
"I thought that this episode of Doctor Who was very good. I thought it was weird that Professor River Song had a sonic screwdriver. I think that Steven Moffat has tried to scare people a lot more, like he did with last year's episode Blink. I can't wait for the next episode it is so exciting! Just remember, stay out of the shadows..."
Lauren, 14, Cardiff, Wales
"I loved it! it was a terrific end, Do YOU think that Donna has been saved, but has not survived? I think so! But I do not know so. As all ways, the Doctor will leave a surprise so I guess I'll have to wait and see."
Zoe, 11, North Ayrshire, Scotland
"Talk about the best episode! Everything is a big mystery. My dad says the pyramid of Mars is better, but how can that be right!?"
Zohra, 9, London, England
"I think it was really mysterious and the dead person was really creepy. Steven Moffat did a great job writing the episode and it's my favourite episode so far."
Luke, 9, Durham, England
"This is the scariest episode of Doctor Who that I have seen. There was superb acting as well as a great story line."
Dilan, 10, West Bromwich, England
"I don't think this episode was very good compared to all of the other episodes."
Jasmine, 10, Argyll, Scotland
"It was good because the skeleton that was moving was scary. I think the lady who knew the Doctor might be Rose in disguise, but I am not sure."
Owen, 6, Braintree, England
"This episode was fantastic! It was really spine-tingling and mysterious. I almost screamed when the Doctor said 'You have two shadows'. And what happened to Donna?"
Emma, 12, Manchester, England
"The episode was amazing, from the mysterious character to the emotional scene where Donna's head was trapped inside the marble pieces. I can't wait for the next episode!!!! 10/10"
Alana, 11, Manchester, England
"That was such a good episode! I'm sad that Donna is dead though, what would Donna's dad and mum think? And anyway, I thought that Rose was in that episode!
100,000 out of 5."
Rosa, 9, London, England