A blonde French peasant girl who witnessed her parents' deaths, Hélène traveled to Calais hoping to find Jean, her uncle and last remaining relative, and start a new life with him. Much to her dismay, Jean sold her to the Middle Man when she was a teenager.
She was captured inside the Middle Man's carriage on 7 February 1788 and witnessed the attempted kidnapping of the French Templar Élise de la Serre. Too afraid to fight back, Hélène could not help the struggling girl and only managed to watch the thugs. Fortunately for them, a drunk ship captain, Byron Jackson, discovered the crime in progress and fought off the thugs with Élise's fallen sword. The Middle Man attempted to escape with Hélène, but at the last moment, Élise sprinted after them and managed to grab Helene's outstretched hand, dragging her out of the carriage.
Grateful to her savior, Hélène decided to serve Élise as her handmaiden, even against the latter's persuasion for her to return to her people. The trio sailed on Byron's ship heading towards England. Unaware of proper etiquette and manners, Byron told Élise to teach Hélène the ways of a proper handmaiden.
The following day, Hélène and Élise bid Byron farewell while arriving at the beach of Dover. Hélène discarded her pauper dress and changed into Élise's breeches and waistcoat to look presentable for the Carrolls, a British Templar family which her mistress planned to visit. While Élise spoke to May Carroll, Hélène braved the house's below-stairs life and found their servants more arrogant than their aristocratic masters.
During their stay with the Carrolls, Élise taught Hélène how to read and speak English. The both of them were asked to infiltrate Jennifer Scott's home as maidservants to retrieve Haytham Kenway's letters, documents of great importance to the Templars which were rumored to be hidden within the house. When Jennifer unveiled their identities and true purpose, they were threatened with death, but Jennifer eventually relented, releasing them and entrusting Élise with the letters, believing she could learn from them.
When Élise realized that the Carrolls were their enemies, she sent Hélène back to Dover for her safety. Meeting again on 10 April, Hélène helped bandage Élise's mentor Frederick Weatherall's gun wound. The trio stayed at Maison Royale's headmistress Madame Levene's home, where Élise apologized for the dangers she had given to her handmaiden. Hélène replied that she would forever be indebted to Élise, knowing that her fate with the Middle Man would be unfortunate if she had not been saved.
Hélène stayed as Jacques' helper and eventually developed feelings for him in the Maison Royale as Élise continued her education. During Élise's hunt for justice, the lovers continued to aid her with Weatherall and eventually got married.
In September 1794, they received letters from Madame Levene, informing them that their mistress was killed, and from Élise herself, saying that the Assassin Arno Dorian would pay a visit to collect her belongings and journals. When Arno arrived, they encountered Bernard Ruddock, who grabbed Hélène and threatened to take her to the Carrolls to collect her bounty. Fortunately, Weatherall and Arno were prepared and managed to kill him.
Hélène and Jacques offered Arno to live with them and stay in Élise's bedchambers, which Arno accepted, much to his gratitude.