Dodo Chaplet

Dodo Chaplet — formally, Dorothea Anne Chaplet (MA: Who Killed Kennedy) —  was a companion of the Doctor near the end of his first incarnation. He took to her within seconds of their first encounter, citing her physical similarity to his granddaughter. (DW: "Bell of Doom") Indeed, she was perhaps most notable for being the first female since Susan to have travelled alone with the Doctor, and the first female human ever to do so. (DW: The Savages / The War Machines)

She had relatively limited contact with other companions, only having spent significant time with Steven Taylor. She briefly met Polly Wright in 1965's London — and was with her when she first encountered Ben Jackson. Still, the relationships were superficial, and neither Ben or Polly had yet seen the TARDIS when Dodo decided to stop travelling with the Doctor.

Aside from those companions who were actually American — and discounting Martha Jones' walk across the globe that never happened — Dodo was likely the companion to have travelled most broadly in the United States. She visited Florida, New York City (PDA: Salvation) and Arizona. (DW: The Gunfighters) Indeed as a percentage of her total travels in the TARDIS, she almost certainly had the most visits to America. She was also one of the few companions known to have lost her virginity whilst an active TARDIS traveller. (MA: The Man in the Velvet Mask)

However, most details of Dodo's life — her childhood, the reasons she both started and stopped traveling with the Doctor, and even her death — were shrouded in a confusion created by several highly contradictory accounts.

Early life
Dodo's grandfather was French and she came to live with her great-aunt at some time prior to joining the First Doctor on his travels. Her relationship with her great-aunt was likely strained, as she believed that she wouldn't be missed. (DW: "Bell of Doom") Furthermore, she expressed delight that she was not, in fact, going to be taken back home anytime soon. (DW: "The Steel Sky")

She was not a good student, and likely never made it to sixth form, much less university. (PDA: Salvation) She didn't speak or understand French, for example, largely because she skipped her French lessons in school in order to learn how to kiss behind the school gymnasium. (MA: The Man in the Velvet Mask)

Beyond these generalizations, accounts of her youth widely differed on the details.

According to one view, she grew up in one of the poorest parts of London, but when her parents died, she moved in with an aunt — possibly not a great-aunt — who was financially more comfortable than her parents. Moreover, her aunt was a social climber, which afforded Dodo exposure to a wide variety of social experiences in her young life. She had difficulty believing that the squalid existence into which she'd been born, and the world to which her aunt aspired, were part of the same reality. As a coping mechanism, she continually reinvented herself depending upon the situation in which she found herself, claiming to have "acted all [her] life". Thus, her accent was situational. (MA: The Man in the Velvet Mask)

An alternate account of her youth claimed that Dodo's parents did not both die when she was young. Rather, Dodo's mother had died in an accident. Her father suffered a mental breakdown and had to be hospitalized, but he was still very much alive at the time of Dodo's first encounter with the Doctor. Nor were her parents poor. This account of her life maintained that her parents were wealthy enough to take her to the Florida Everglades — a trip that left her with a deep appreciation for the variety of life on Earth, and a desire to see more of the world. Nevertheless, after the death of her mother from unknown causes, Dodo was sent to live with her great-aunt, Margaret. Amongst other things, she forced Dodo into elocution lessons, which allowed Dodo to develop a "natural" and a "posh" accent. Life with her formal great-aunt also caused her to see herself in two ways: "Dorothea", the proper young lady Margaret wanted her to be, and "Dodo", the somewhat plain kid at school she probably really was. (PDA: Salvation)

Nickname
How she got the nickname "Dodo" was no clearer than any other part of her youth. According to one view of her childhood, it was an appellation given to her by her classmates. At some point after she went to live with her great-aunt, she was forced to switch schools mid-term. Her new classmates ridiculed her north-of-London accent, thinking it made her sound ill-educated. Thus, they nicknamed her after the Dodo, an extinct bird believed to be stupid. Instead of rejecting the name, she instead tried to change people's perception of the name by nearly becoming "cool". (PDA: Salvation) As an adult, she intimated to James Stevens that she didn't know where it came from — though her memory was notably unreliable at the time. (MA: Who Killed Kennedy)

Meeting the Doctor
Dodo's great-aunt also forced her to spend time helping an elderly neighbour do his shopping and other menial tasks. One night, an alien ship crashed nearby and its pilot killed the neighbour, assuming his physical form. When Dodo learned what happened to her friend, the alien kept her prisoner for some time, until she was able to escape. When she did escape, she rushed across Wimbledon Common, heading straight for what she thought was a police box — but was, in fact, the TARDIS. According to this view, then, Dodo met the Doctor because she was fleeing from an alien. (PDA: Salvation)

However, yet another account maintained that, as a young adult in the 1960s, Dodo witnessed a small boy getting hurt. Seeking help for the child, Dodo spotted a police box on the common and entered it. Instead of a policeman, she found the Doctor. (DW: "Bell of Doom")

Regardless of which view was correct, one thing was true: like Tegan Jovanka and her Aunt Vanessa, Dodo was one of only a few people to ever attempt to use the TARDIS as an actual police box.

Initial trip
Just as he had done with Ian Chesterton and Barbara Wright, the Doctor dematerialised the TARDIS without giving his new passenger a choice in the matter. This time, however, the cause was slightly different: approaching policemen would have forced their way into the TARDIS had not the Doctor taken off. Steven protested, but wasn't able to counter the Doctor's logic. (DW: "Bell of Doom")

Dodo's first trip in the TARDIS was merely one in space, not time. They went to New York City in 1965, where they met and defeated the compatriots of the alien who had briefly kidnapped her back in London. (PDA: Salvation)

Other travels
After New York, the TARDIS crew found themselves on the Ark. At first, she believed that they were at Whipsnade Zoo. Dodo told the others that she went there as a child, and she displayed some knowledge of nature. Unfortunately, Dodo had a cold, and this virus was accidentally passed on to the humans and Monoids inhabiting the Ark. As they had no resistance to this virus it became a plague. Dodo, being a caring person, was distraught that she had caused this terrible event. (DW: The Ark)

Dodo's caring nature was probably what made her dislike cheating, unfair, behaviour. Whilst this annoyance could be seen at many times, it was most visible when the travellers met the Celestial Toymaker. It was his games, attitude, and Cyril's cheating which frustrated Dodo. (DW: The Celestial Toymaker) Whilst travelling with the Doctor, Dodo was lucky enough to have one of her life-long wishes granted. She was keenly interested in the Wild West, and revealed that she had always wanted to meet Wyatt Earp. When the travellers arrived in the American West, the Doctor introduced Dodo as "Miss Dodo Dupont, Wizard of the ivory keys". During their time in this era the Doctor noted that Dodo was "fast becoming a prey to every cliché-ridden convention in the American West." (DW: The Gunfighters) Despite this, and the sad events on the Ark, Dodo's interest, and excitement, were still evident as the travellers continued on their journey. Dodo was not frightened to investigate on her own, and on the next planet they visited she wandered off while the Doctor and Steven were busy with the Elders and the Savages. She had a look around this planet, and discovered the laboratory of Senta, which was used for the life-force transferance that kept the Elders alive. (DW: The Savages) After Steven's departure, she traveled alone with the Doctor for an indeterminate amount of time. During this period, it became obvious to her that the Doctor was becoming increasingly frail. At one point, he explicitly said that she would have to leave the Ship, as Steven had done, because he had to face up to the next phase of his life alone. During this somewhat melancholy period, where Dodo often had to nursemaid the Doctor at times, they arrived in a kind of alternate timeline in France, and had to defeat a man intent on unleashing a virus that could've taken over the world. While on this "alternate Earth" Dodo believed she contracted the virus through by losing her virginity to a known carrier — although it was not definitively known whether she had the condition positively diagnosed. When questioned, she said that she wanted to keep the virus as a reminder of the world that had been lost when the timeline righted itself. (MA: The Man in the Velvet Mask)

At some point thereafter, she and the Doctor arrived in 1966 London and discovered WOTAN and its War Machines. WOTAN conditioned her to betray the Doctor. On discovering this, the Doctor broke her conditioning, and sent Dodo to the country to recuperate. Dodo never returned, instead she sent her TARDIS key back with Polly, saying that she had decided to stay in London. (DW: The War Machines)

Life after the Doctor
Accounts of Dodo's life after leaving the TARDIS differed.

By one account, Dodo would suffer severe and recurrent psychiatric problems as a side effect of being controlled by WOTAN. Shuttled from hospital to hospital, she was eventually sent to the Glasshouse, where she was brutally interrogated by its director, the Master, about the Doctor. Turned out into the street, the homeless Dodo eventually met and fell in love with journalist James Stevens, at that time investigating the activities of UNIT. While Stevens was being interviewed on a live television broadcast, Dodo was murdered by Francis Cleary, a former UNIT soldier, Glasshouse patient, and another of the Master's hypnotically controlled pawns. Only after her death did Stevens learn that she was carrying his child.

The Doctor, in his second or seventh incarnation appeared at the funeral and attempted to give solace to Stevens. (MA: Who Killed Kennedy)

Another account suggested that she couldn't have been murdered by the Master's agent. According to this view of her post-TARDIS life, she had gone on to a rather mundane career as a secretary. The torpor of her life made her regret her decision to leave the Doctor and long, in adulthood, for a chance to travel in the TARDIS again. She thought that she'd be better able to appreciate such travels, now that she was "older and wiser". It was during a particularly nostalgic moment that she accidentally bumped into Sarah Jane Smith, though the two didn't recognize each other as friends of the Doctor. (BE: Ships)

Will the real Dodo Chaplet please stand up?
As on television, where she only had about four-and-a-half stories, Dodo is one of the least-featured companions in other media. Unfortunately, most all of these other appearances conflict with each other. The Man in the Velvet Mask opposes Salvation over what Dodo's childhood was like. Salvation differs with "Bell of Doom" over why she initially approached the TARDIS in Wimbledon Common. Mask, Who Killed Kennedy and Ships all disagree over what might have killed her in the 1960s or 1970s — or even whether she died at all in those decades. To be sure, other companions do have stories which differ over the odd biographical detail. For example, we can wonder, thanks to SJA: Death of the Doctor, whether Liz Shaw actually died in NA: Eternity Weeps  However, the degree of difference between individual Dodo stories is unusually high — approaching that of Ace, who effectively has several largely irreconcilable alternate timelines.

Did Dodo die from syphilis?
There is a widespread belief in fandom that Dodo's fate in the novels is that she contracted syphilis. This view was taken, for instance, by the long-running podcast, Radio Free Skaro, some of whose hosts vociferously maintained in episode 177 that she "died of of syphilis" in Who Killed Kennedy. Indeed, even David Bishop, the author of Kennedy, said in his notes to the e-book version of his novel that Dodo contracted "an illness interpreted by some as a form of space herpes".

All that's pretty wide of the mark, however. The idea that she died of syphilis is a common conflation of the two stories: Who Killed Kennedy — where she's simply killed by the Master — and The Man in the Velvet Mask — where she contracts the genetically-engineered Minski's virus through sexual contact. However, she doesn't die from it, nor was it even possible for her to do so, according to the Doctor. Minski's virus wasn't anything close to a venereal disease, and could have been contracted by drinking water or consuming food contaminated with it. Perhaps more to the point, the word syphilis doesn't occur even once in either novel. She does have two sexual tragedies in Kennedy, however: she admits to having killed her would-be rapist in unarmed combat, and she is murdered while pregnant.