Helen Sinclair was a companion of the Eighth Doctor.
Biography
Before the Doctor
Helen was a language scholar for the British Museum during the 1960s. Her career was stymied by the misogynistic attitudes of the time, and the "old boys" network working against her. Despite being more than qualified for a promotion, she was denied the position by her superior who felt she wouldn't be able to commit fully due to the "fact" that women were "too emotional." (AUDIO: The Red Lady)
Helen had never been abroad until she travelled with the Eighth Doctor, and carried a box brownie camera with her. (AUDIO: The Galileo Trap)
Meeting the Doctor and Liv
In 1963, while working as an assistant to Professor Walter Pritchard, she met the Eighth Doctor and Liv Chenka, who were in search of a temporal anomaly related to the Eleven. Joining them whilst they investigated a collection of artefacts featuring the Red Lady, she became involved in a mystery involving extraterrestrial elements. Not having seen any of the artefacts featuring the entity, Helen was unaffected by her influence, and was able to help prevent the Doctor and Liv from succumbing to her effects. After they defeated the Red Lady and the artefacts were "disposed of," Helen was dismissed from her position and threatened with being reported to the police, her boss being suspicious that she was behind their theft. Impressed by her help, the Doctor offered her the chance to join him in the TARDIS, which she accepted. (AUDIO: The Red Lady)
Arriving in Florence in 1639, she was immediately fascinated by the opportunity to visit history, so much so that she wished she had brought her camera so she could take pictures of it. She joined Cavalli in investigating Cleaver and saw her first spaceship, helping the Doctor and Galileo to defeat him and Fortuna, his fellow Volkbrood. (AUDIO: The Galileo Trap)
She was used in the Eleven's game against the Doctor, being captured by an Orb aboard the Eleven's stellar manipulator and prepared for dissection. However, Paine arrived and stopped it, allowing her and Liv to flee to the TARDIS. (AUDIO: The Satanic Mill)
Freeing the Sonomancer
After this ordeal, the Doctor took her and Liv to Stegmoor to recuperate. She wanted to go somewhere a bit more alien. She helped to move the Doctor when he fell unconscious. She told the Doctor about the Voord spaceship on the beach. (AUDIO: Beachhead) She couldn't understand the dimensions of the antique TARDIS. Caleera used her powers to empathise with her. (AUDIO: Scenes From Her Life)
When they landed in San Francisco in 1906, Liv trusted her to guide her around the city as it was closer to her time than Liv's. She was taken by Aldo Deluca because he wanted to know about the Gift. (AUDIO: The Gift)
On Syra, Ruslan tried to threaten her into telling the truth and then trapped her with River Song. She helped River to contact Galactic Heritage and promised to keep her secret. (AUDIO: The Sonomancer)
Defeating the Doom Coalition
When she realised they had landed in Calcot in 1998, she decided to take a train back to London to discover what had happened to her friends and family. In London, she went to her old house and found out that it had been converted into flats. She later went to see her brother George Sinclair. George then told her about how their mother, father and brother had died. After telling the Doctor she could just go back, he told her this was impossible. She was now part of events and could not go back and change her own timeline. (AUDIO: Absent Friends)
She was sent by the Doctor to Rome in 2016 in order to find a piece of the Doomsday Chronometer. She met Rosalia who showed her the collection of clocks in the museum she worked with. There she met the Clocksmith. (AUDIO: The Eighth Piece)
Before entering the museum, she met River again, who told her to come with her on a scavenger hunt to help her find the Eighth Piece. She collected many paintings and discovered where the Eighth piece was and took it back to Rome. She was then frozen in time for the Clocksmith's enjoyment before the Doctor arrived. She managed to escape the collapsing museum and went back to the TARDIS just in time to see Whitley regenerate. (AUDIO: The Doomsday Chronometer)
Liv had to explain the effects of regeneration to her after witnessing it. After the Nine told her that Liv had died on Gallifrey, she wanted to leave, before she discovered that he was the Nine. She was appalled at the Nine murdering the Time Lords at the Crucible of Souls. Padrac then revealed he was working with the Eleven, and trapped her, Liv and the Doctor in a scape capsule careering into the nontime of a murdered future by Padrac. (AUDIO: The Crucible of Souls)
The group tried to head back to the Crucible in an attempt to stop Padrac. After seeing some pressure suits she thought of jumping out and swimming in the other direction. She tried to calm Liv down after she became upset. They jumped out of the pod and rode the shockwave back into normal time. (AUDIO: Ship in a Bottle)
Liv and Helen appeared back in the normal universe with only five minutes of oxygen. They were rescued by a Time Ship which traversed the vortex and started to disintegrate. After Liv managed to get them to Earth she wanted to get to a spaceport to get away from an Earth which was disintegrating. River later told Helen to tell Liv who she was. River managed to get her to Gallifrey where she got to the TARDIS and left with Veklin to find the Doctor. (AUDIO: Songs of Love)
Helen and Liv went exploring New York. When they went to the main museum they saw a picture of the TARDIS and a Weeping Angel which had been bequeathed by them. At the museum they started to hear about the Weeping Angels. The Monk projected an angel which then became an angel in front of them. However, they were saved by Veklin. They joined up with the Doctor again, but the Eleven trapped them on top of a skyscraper. The Monk was sent back in time and Ollistra was pushed off the building, causing a regeneration, but the Doctor, Liv and Helen managed to get away to the TARDIS. (AUDIO: The Side of the Angels)
The group headed to Gallifrey. Helen wanted to join the Doctor in the Panopticon but he wouldn't let her, instead she was tasked in evacuating the Time Lords. When the Eleven escaped from his restraints he stole a Battle TARDIS and kidnapped her. Caleera contacted her via the Matrix, granting Helen the telekinetic powers of the Sonomancer. She was able to stop the blast from the Eleven's staser with her mind. Caleera got her to crash the TARDIS into the Resonance Engine to defeat the Doom Coalition. The Battle TARDIS wasn't destroyed in the blast, so the Doctor and Liv went searching for it. (AUDIO: Stop the Clock)
Reunion with the Doctor and Liv
The Battle TARDIS crash landed on Rykerzon, and Helen and the Eleven were taken as prisoners. During that time, Helen cared for the Eleven and tried to help him control his condition and suppress the voices of his other incarnations. She would sing to soothe him, and he pretended to reciprocate, and called her his saviour. When the Eighth Doctor and Liv arrived looking for Helen, she was thrilled to see them again, despite the Doctor being skeptical of her. Eventually, the Eleven joined with the Kandyman to take over Colony 23, a plan which was then stopped by the Doctor, Liv and Helen. Helen was then welcomed back on board the TARDIS. (AUDIO: World of Damnation, Sweet Salvation)
Behind the scenes
In the behind the scenes extras to Doom Coalition 1, producer David Richardson cites Verity Lambert as a source of inspiration for the character of Helen Sinclair, something acknowledged in her coming from 1963.