The story begins with the mysterious Doctor Who confronting two schoolteachers who have forced their way aboard his Ship. The writer has not yet thought of a name for the Ship, but has decided that Doctor Who’s granddaughter, Susan, will name it from its initials. The writer is also unsure whether he should identify Doctor Who as a space traveller from Venus in the 49th century, or to keep his origins secret. But he’s very happy with the way the story is progressing, especially when Doctor Who ponders his and Susan’s lives as outcasts, adrift in the dimensions of space and time...

But Martin Bannister’s nurse wakes him at this point, interrupting his dream of writing. The nurse gently berates Martin on the mess in his room, particularly the unearthly green stain by the wardrobe, and informs him that he has a visitor. Martin is surprised when the young man from his dream walks in, but it’s not Ian Chesterton; it’s Martin’s son, Philip. The nurse politely takes her leave, and Philip, grimly pleased to have found his estranged father in a seedy nursing home, informs him that his ex-wife -- Philip’s mother, Amy -- is dead and that Martin wasn’t invited to the funeral. Martin, though saddened by the news, is amused by the fact that his wives appear to be dying in the wrong order; his third wife died some time ago and his first wife is still alive. Furious, Philip lashes out at his insensitive father, who walked out on Amy and Philip when Philip was only six years old. He also informs his father that he’s happily married and has a son who loves him -- because he does everything exactly the way that Martin didn’t.

Martin is shocked to learn that he has a grandchild, but Philip refuses to let him ever meet Tom and instead prepares takes his leave. On his way, he asks Martin how his writing is going, and Martin admits that he’s run out of things to say. He always put writing above everything else, even his own family, and Philip is perversely pleased to learn that he’s lost the ability to do that. The nurse returns, and is intrigued to learn that Martin used to be a writer; she too used to write poetry. Martin admits that he used to be a highly acclaimed playwright, and that he wrote some episodes of Juliet Bravo. The nurse offers to read Martin some of her poetry, and though he tries politely to put her off, he’s caught off guard when he learns that her name is Barbara Wright, just like the character in his unwritten script. He agrees to listen to her poetry, though she obviously doesn’t regard writing with the passion that he used to. Sometimes he thinks he sold his soul for his art...

The story continues. Doctor Who claims to have taken his ship back to the time of Hannibal, which Ian finds hard to believe. The story pauses for a moment as Martin tries to work out whether the character is actually named Doctor Who or not, but he puts the question aside for the moment and continues. The travellers emerge from their ship in a petrified alien forest, which gives Martin cause for concern; what will Sydney Newman think of this new direction? There are unearthly green stains like alien footprints on the forest floor, and claw marks gouging out the wood on a nearby tree -- and before Doctor Who and his companions can return to the ship, they are menaced by a bug-eyed monster!

Once again Martin’s dreams are interrupted by a visitor; this time it’s Sydney, a writer for the Official Juliet Bravo Magazine. Martin Bannister is the only person involved with the show who hasn’t been interviewed to death, and he eventually agrees to the interview once he realises Sydney intends to pay him for it. He begins to speak about his work as a renowned young playwright, but Sydney apologetically cuts him off and asks him to concentrate on his work for Juliet Bravo. Martin is less enthusiastic about this subject, claiming that his 14 episodes were all pretty much the same -- and that the show itself was just cheap time-wasting filler and not worth analysing. He believes that his work on Juliet Bravo was a symptom of his failing career, and feels that he should have walked out on the show and gone back to writing for the theatre. Instead, he wasted his life and his talent writing disposable television shows for quick money, and eventually he stopped writing at all, because he’d run out of things to say.

As the bitterness pours out, Martin wonders if he’s dreaming of Doctor Who because that’s where it all started to go wrong. Martin was hired to write the first episode of this imaginative new science fiction series devised by an Australian (or Canadian, Martin can’t remember) producer named Sydney Newman, but the BBC got cold feet at the last moment and fired Newman. Since Martin was still under contract, they moved him over to the uninspiring Juliet Bravo, and his career never recovered. Sydney scoffs at the concept of an old man travelling the Universe in a police box, and Martin angrily suggests that Sydney might be more than a journalist for a niche magazine if he’d grown up watching an imaginative science fiction programme rather than a dull-witted police drama. This is the last straw, and Sydney angrily reveals that all of Martin’s episodes are loathed; to Juliet Bravo fandom, his name is a joke. Sydney storms out of the room, leaving Martin stunned by the revelation that nobody liked his work -- not even the early episodes, when he was actually trying to do his best.

That night, Barbara reads her poetry to Martin, who tries desperately to be polite about it -- until she describes the colour of flowers as a “tardis blue.” The strange word strikes a chord within him, and he finds that he’s been inspired to write once more. He dismisses Barbara, but as she gets up she notices more green stains, like alien footprints leading from the wardrobe to Martin’s bed -- where the headboard has been gouged as if by alien claws. Martin realises that there’s an alien hiding in his wardrobe, but he doesn’t know what kind, because he hasn’t named it yet. Barbara opens the wardrobe and assures Martin that there’s nothing hiding there, although the wardrobe is now larger on the inside than the outside. Terrified, Martin begs her to help him move the dresser in front of the wardrobe, blocking the door so nothing can get out and hurt him. She humours him and does so, and is delighted when he absently agrees that she’s a talented writer, although he’s saying so just to get her out of the room.

Martin desperately tries to stay awake, but despite his efforts to keep the monster at bay, it bursts out of his wardrobe... and is revealed to be his grand-daughter, Susan, who claims that everyone is waiting for the story to begin. Martin dismisses her, claiming that he has no grandchildren, but then remembers that he does -- a grandson named Tom. He tries to dismiss the imaginary Susan, but she’s too innocent and loves him too much for him to feel comfortable doing so. Though it’s 2:00 in the morning on a Tuesday, she claims that it’s really a quarter past 5:00 on Saturday afternoon; after all, time is relative. Susan takes Martin’s hand and leads him into the wardrobe, which is really the TARDIS -- a name she made up from the initials Time And Random Destinations In Space...

And so Doctor Who and his companions set off on an exciting adventure, but they soon fall foul of a being known as the Supreme One. As his companions die of radiation poisoning, Ian blames Doctor Who for bringing them to this planet; what kind of father would do that? Doctor Who denounces the evil of the Supreme One, but the Supreme One points out that Martin just wants him to be perfectly evil because that makes him easier to write. The Supreme One begins to sound somewhat like Sydney as he derides Martin’s poor characterisation; how can he hope to be a successful writer if he doesn’t understand people? As Doctor Who and his dying companions are marched off to the dungeons, Ian accuses him of abandoning his wife and child, and Martin, or Doctor Who, realises that he has no idea how to save his companions.

Philip returns to the nursing home, claiming that he’s decided his father deserves a portion of Amy’s ashes. An awkward silence follows, and Philip finally comes out and asks Martin why he abandoned his family. Martin admits that he wanted to produce masterpieces, and that he found ordinary life with a wife and son too uninspiring. Now, decades later, he’s finally forced to admit that he was never a good writer anyway, and that he gambled away his family’s happiness for nothing. Philip caves in and admits that Amy is alive after all; he bought and killed a pet guinea pig just so he’d have some ashes, because he couldn’t visit his father without some excuse. The truth is, despite Philip’s desperate efforts to be a good husband and father, his wife still left him, he only gets to see his son every other weekend, and he doesn’t understand why. He visited Martin in a desperate attempt to find out what his father had done to make him this way, but now must admit that he’s simply failed at life. He hopes that he can finally make amends with his father, but Martin sadly points out that they’ve nothing in common. It’s too late for them -- but perhaps Martin can still have a chance to put things right with his grandson. Philip reluctantly agrees to bring Tom to the nursing home on Saturday so they can meet, and, freshly inspired, Martin finds that he can write again.

That night, Martin receives an imaginary visit from Sydney Newman, whose accent changes from Canadian to Australian and back as Martin tries to remember which country he’s from. Newman claims that the BBC have decided to celebrate the 40th anniversary of Doctor Who by finally putting the programme on air, and Martin shows Newman the first draft of episode 1, promising him an educational script with as few bug-eyed monsters as possible. This might be just what Martin needs to revive his career. Newman is then replaced by Susan, who asks her grandfather why he’s talking with imaginary people and invites him to set off on another adventure. But Martin doesn’t want the distraction, and as he berates Susan for interrupting him at his writing, he inadvertently refers to her as “Amy”. Susan reads the script which Martin has written, and notes that he has more lines than she does -- but Martin points out that he’s the hero, and she’s just a sidekick.

Barbara Wright then enters the room -- the nurse, not the schoolteacher -- and tells Martin that he’s inspired her to start writing poetry again. She’s been drinking some wine, working up the courage to speak with him, and Martin sends Susan back to the wardrobe while he speaks to Barbara. Barbara confesses that she’s very lonely; she was engaged to a science teacher named Ian Chesterton once, but he abandoned her without a word, as if he’d dropped right off the face of the Earth, and she’s never forgiven him for it. She became a nurse in order to make life better for other lonely people, and has wasted her life tending to old forgetful folk with poor bladder control; but now that she’s met a fellow writer, she feels as though she finally has a kindred spirit.

Martin understands what she’s saying, and realises that this is the reality that’s been missing from his scripts all along. Or so he thinks until he tries to kiss her and she recoils in disgust. He’s far too old for her; all she wanted was a friend she could talk to. Disgusted, she tears his script to shreds, telling him that he has no right to call himself a writer if he doesn’t understand people. She then storms out of the room, leaving Martin to scrabble about for the pieces of his ruined script, looking for an intact scene.

In the dungeons of the Supreme One, Ian has died of radiation sickness, and Barbara dies as Doctor Who watches (somewhat to his satisfaction). Susan, saddened, doesn’t understand when their adventures stopped being fun, but Doctor Who now knows that he needs more reality in his life. He thus informs Susan that he’s going to leave her here and go find his real grandson, Tom. Susan begs him not to leave, but he tells her that their relationship just doesn’t work; if he is to succeed, he must understand what he’s been missing. As he speaks, Susan seems to metamorphose into his wife, Amy, who begs him not to leave her. He’s treated her badly, but she still loves him, and doesn’t understand when their marriage stopped being fun. However, Martin claims that their marriage just doesn’t work, and he leaves Amy to a sad and lonely life, just as Doctor Who leaves Susan to a sad and lonely death.

It is Saturday, and as promised, Philip has brought Tom to meet his grandfather. But Tom is absorbed in a handheld video game and isn’t paying attention. Martin asks Philip to give them a few minutes alone, and Philip reluctantly steps outside. However, Martin’s attempts to engage Tom in conversation are dismal failures. Tom doesn’t care about the motivations of the alien invaders in his video game, and has no interest in discussing what he wants to be when he grows up. Martin confides that he’s failed at everything in his life -- his writing, and his family -- and that Tom is all he has left. But as far as Tom’s concerned, his grandfather is trying too hard to be his friend, just like his father does.

Realising that his chance to put things right is slipping away from him, Martin tells Tom his great secret. He is Doctor Who, and his wardrobe is really a ship for travelling through time and space. If Tom has faith and gets into the wardrobe with him, then they can travel the Universe together and have glorious adventures. Tom, disgusted, tells his grandfather to piss off, and Martin slaps him, enraged by this rejection. Philip bursts in, furious, and sends Tom out of the room, claiming that Martin is completely mad.