10 Dropped Doctor Who Plot Threads We'll Never Get Answers To

While this isn't an abandoned plot thread exactly, it's still an abandoned and untapped story idea, one that we'll probably never see more of.

In the first half of the Series 5 finale, the Doctor is captured and sealed inside the Pandorica, an inescapable prison that was specifically built to contain him. And which villain was responsible for this ultimate victory? Well... all of them.

This "Pandorica plan" was engineered by a group known as The Alliance, a league of bad guys that combined forces to achieve one mutually-beneficial goal: stopping the Doctor. Despite consistently failing as individuals, they were successful as a team, and for a brief time, the Doctor had been unequivocally defeated.

So why has The Alliance never been formed again since? The Daleks, the Cybermen, the Sontarans, the Judoon, the Autons... together, they managed to defeat their greatest foe, so it does seem strange that they've never again considered putting aside their squabbles to focus on the one being who actually threatens them all.

Sure, the events of The Big Bang mean that the members of The Alliance won't remember their Pandorica victory, but regardless, they must know that they'll stand a better chance against the Doctor as a unit. However, the topic of villainous team-ups - at least, on the scale of The Alliance - hasn't been broached in the decade since Series 5 aired. Realistically, we'll never see an evil league like this again.