Agatha Christie's 10-day disappearance in 1926 may have been the result of amnesia, a nervous breakdown, or a giant alien wasp.

The mysterious Lady Christina de Souza joins the Doctor on a bus trip which takes a very unexpected detour into danger.

Mars, 2059. Bowie Base one. Last recorded message: don't drink the water. don't even touch it. not one drop... Confused? All will be revealed in The Waters of Mars, starring Lindsay Duncan as the Doctor's cleverest and most strong-minded companion yet.

As the story continues, Rose battles the murderous Ood and the Doctor finds his every belief being challenged to the core, as the Pit beckons. With the planet threatening to fall into the Black Hole, the Doctor must make the ultimate sacrifice - but can he save the entire universe from the Beast?

The Doctor finds himself the reluctant Sheriff of a Western town under siege by a relentless cyborg.

As the ghosts of loved ones return home, an almighty invasion force threatens to take over Earth.

The Time Lord takes Donna far into the future, visiting her first alien world. The duo discover shocking truths about the human race while on the planet Ood-Sphere, as the enslaved inhabitants struggle for survival. Tim McInnerny guest stars alongside David Tennant and Catherine Tate

The Doctor finds himself the reluctant Sheriff of a Western town under siege by a relentless cyborg.

An ordinary man called Elton becomes obsessed with the Doctor and Rose and their mysterious blue box. But when Elton's investigations bring him to the attention of the enigmatic, cold and powerful Victor Kennedy, his harmless hobby suddenly plunges him into a living nightmare.

An ordinary man called Elton becomes obsessed with the Doctor and Rose and their mysterious blue box. But when Elton's investigations bring him to the attention of the enigmatic, cold and powerful Victor Kennedy, his harmless hobby suddenly plunges him into a living nightmare.

The Doctor makes a house call for a boy who is terrified of the monsters lurking in his bedroom cupboard.