Bill Pots' life is about to change forever when a professor at the university where she works -- who goes by the name "the Doctor" -- takes her under his wing. But when a friend introduces Bill to a strange puddle of water, she becomes the target of an alien intelligence.

The Doctor takes Bill on a trip to the far future, where they find an idyllic colony manned by Emojibots waiting for the arrival of colonists from Earth -- and which conceal a dark secret about the fate of the scientists assigned to the colony.

In nineteenth-century England the Doctor and Bill find a festival on the frozen surface of the Thames, and soon discover that a humongous creature lies beneath the feet of the city's poor and unsuspecting citizens.

Bill moves into a creaky old house with a group of new roommates and a rent too good to be true. And when the Doctor shows up to help her move in, they find that the landlord is hiding a disturbing secret inside the house's walls.

When the Doctor and his companions answer a deep-space distress call they find themselves trapped on a space station where oxygen is sold by the breath. And their discovery that most of the crew is dead is complicated when the murdered scientists begin walking again.

A troubled Vatican appeals to the Doctor for help after every person assigned to read an ancient heretical text called the Veritas ends up dead by his own hand. While the Doctor struggles to hide a secret from Bill, he recalls the part he played in Missy's execution.

An ancient pyramid mysteriously appears in the midst of Earth's three most powerful armies, signaling an alien invasion unlike any before -- where the invaders quietly wait to be invited to take control of the planet in order to avert a coming disaster.

With the world under a spell since the Monks took control and began to actively rewrite the memories of every person on Earth, Bill goes in search of the Doctor -- who seems to be colluding with the invaders.

A message from the past sends the Doctor and his companions to the underground tunnels of Mars in 1881, where a lost squadron of soldiers from the Victorian era have made a pact with the lone survivor of the Ice Warriors. With a conflict brewing, whose side will the Doctor take when the Earthlings are the invaders?

In second-century Aberdeen the Doctor and his companions go in search of the fate of the Roman empire's ninth legion -- but find an inter-dimensional predator that feeds on sunlight and that threatens the whole world.

The Doctor tasks Missy to lead a rescue mission to a colony ship on the edge of a black hole. But when someone he is pledged to protect is shot, does the Doctor have any way to save her when time is no longer on his side?

While Nardole helps to lead the colonists away from the attacking Mondasian Cybermen, the Doctor attempts to convince Missy and the Master to help him -- even though it may lead to all of their deaths.