With Series 10 of Doctor Who we have the mystery of the vault? Who is in it? Why did the Doctor swear an oath to protect it? And who did the Doctor swear this oath to?

We will probably not get answers to these questions until the last few episodes but what does appear certain is that the vault is the story arc that will run throughout this series. Now we have had series-long arcs in Classic Who – the Third Doctor battled the Master for the entirety of Season 8 and the Fourth Doctor searched for the pieces of the Key to Time for all of Season 16 – but they have become mandatory for Nu Who.

For this post we will be ranking the previous nine series-long arcs based on the concept, how they were threaded throughout the episodes and how they were resolved. Here is your SPOILER ALERT for everything up to Series 9. Still here? Well then Allons-y, Geronimo and here we go!

#9 The Hybrid, Series 9, Twelfth Doctor

Oh Hybrid, Schmybrid

Who the heck was the hybrid? Was it Me/Ashildr? Was it the Doctor? By the end of the Series 9 I still did not know and, worse yet, I stopped caring. And it had little to do with the plot of the finale which is kind of the point of a series-long arc. A wasted opportunity here.

#8 Death of the Doctor, Series 6, Eleventh Doctor

One day he will be able to walk past an astronaut

Series 6 started off with a bang, literally. The Doctor gets blasted and killed by a mysterious astronaut who comes walking out of a beach. Quite the tantalising mystery. But then it got all convoluted with the River stuff and the Teselecta reveal could have been seen from a mile away. At least we got the sweet mini-arc with Amy’s baby – where is my wife! – and a touching wedding.

 #7 Who is Harold Saxon? Series 3, Tenth Doctor

Subliminal message? What subliminal message?

This was one of the more subtle arcs on this list and if you were not paying attention you would have missed all the references to “Harold Saxon”, who turned out to be the Doctor’s regenerated nemesis The Master. Also the Face of Boe’s message “you are not alone” relating to the amnesiac Master as Professor YANA (You Are Not Alone? Get it?) was too much on the nose. Maybe if we had actually seen and met Saxon before his big reveal then it would have had more of an impact. Sadly the execution falls flat.

#6 Torchwood, Series 2, Tenth Doctor

I don’t need to upgrade. I already have the iPhone 7

Who knew that the mysterious organisation would become a spinoff series featuring good old Captain Jack Harkness. Before that it was the Torchwood Institute which was founded in 1879 when the Doctor and Rose had a run in with Queen Victoria, some deadly monks and a werewolf. This led us to the modern day Torchwood and their questionable experiments which leads to a Cybermen and Dalek invasion. A decent enough series arc but the conclusion used it as a launching pad more than anything else.

#5 The Cracks in Time, Series 5, Eleventh Doctor

All it needs is some spackling paste and grout

There’s, something on the wall. Some…thing! These pesky time cracks just kept popping up. They even swallowed up poor Rory. The mystery deepened when the Doctor pulled out a piece of the TARDIS from a crack. We eventually learned that the cracks were caused by an exploding TARDIS in the future. The concept was interesting enough but the whole wishing the Doctor back and rebooting the universe was the worst kind of deus ex machina. This is not a video game where you can just hit the reset button. Better than that Moffat. Better than that.

#4 The Impossible Girl, Series 7, Eleventh Doctor

Whoa. Trippy…

We met the first incarnation of Clara in the spectacular Asylum of the Daleks and she was a smart, witty chick who just happened to be a Dalek. Then we met a Victorian-era Clara and she was sassy and sweet but then she died too. And then the Doctor meets a modern version and things got a bit, well, boring. Moffat may have been going for mysterious with “The Impossible Girl” but did that have to mean lack of character development? That aside the revelation that Clara had been scattered across the Doctor’s timeline was fantastic. The finale scored points by giving a nod to the previous Doctors and bonus points for showing an incarnation of Clara interacting with the First Doctor and his granddaughter Susan. As the Ninth Doctor would say – “fantastic.”

#3 Missy and the Nethersphere, Series 8, Twelfth Doctor

Have to take over the world. But first, let me take a selfie

Where are all these dead people going? Who is this Mary Poppins-looking lady with the crazy eyes?  These were the nagging mysteries throughout Series 8. We learned that the dead people were in the Nethersphere and would be turned into mindless Cybermen and the kooky lady was a regenerated and gender swapped Master. Say what? It was a great twist and deserving of our bronze medal.

#2 Rose and the Missing Planets, Series 4, Tenth Doctor

Once again Pluto gets the shaft

Like the John Saxon references you may have missed all the disappearing planets throughout this series, probably because we were having so much fun with the Tenth Doctor and the lovable Donna. But it was impossible to miss former companion Rose Tyler popping up all over the place and we were waiting with bated breath for her and the Doctor to reconnect. Their reunion is touching and the disappearing planets being part of a weapon by the Daleks and their creator Davros, not seen since Classic Who, was masterful.

#1 Bad Wolf, Series 1, Ninth Doctor

This is a bad sign

When it comes to season-long arcs nothing beats Bad Wolf. This mysterious phrase appeared over and over during Series 1? Who or what was it? Why is it found throughout time and space? Inquiring minds needed to know. But who could have guessed that the Bad Wolf would end up being an overpowered Rose after she looked into the time vortex in the heart of the TARDIS. And then she destroyed an entire Dalek army. Suh-weet!

The Bad Wolf Rose would return in The Day of the Doctor fiftieth anniversary special but more importantly would become a real world meme for all Whovians. Just say “Bad Wolf” and everybody knows what you mean. Try it. Now that is a powerful season arc.

So what is your favourite Doctor Who season arc? And who do you think is in the vault? Feel free to comment.

For my Top 9 Series of Doctor Who (Part 1) you can click here.