Aveline overheard a conversation between her father Philippe and Gérald Blanc concerning missing goods, and decided to investigate. Aveline searched the docks for the missing goods. Aveline met with Gérald Blanc, who informed her of a Templar being present at a party. Aveline set out to find a way into the mansion where the party would be held. Aveline infiltrated the governor's mansion and uncovered a Templar conspiracy. Following her assassination of governor d'Abbadie, Aveline became highly notorious and fled to the Louisiana Bayou for safety.

Following her assassination of governor d'Abbadie, Aveline became highly notorious and fled to the Louisiana Bayou for safety. Having followed Agaté's clues, Aveline found her way to her Mentor's hideout, where she was informed of the recent threat in the bayou. After having been told of the false Mackandal and mastered the use of the blowpipe, Aveline returned to her Mentor for her next instructions. Aveline and her new ally, Élise Lafleur, set out to take down the first camp of the false Mackandal. Following her elimination of the false Mackandal's first camp, Aveline reunited with Élise Lafleur, who guided her to another encampment. Aveline traveled to San Danje to meet with the houngan living there, in the hopes that he could help her find the location of the voodoo ceremony held by the false Mackandal, whom she had been ordered to kill. Following her assassination of Baptiste, Aveline returned to Agaté to explain what had happened.

In an attempt to find out more about Rafael Joaquín de Ferrer's activities, Aveline set out to question Carlos Dominguez. While practicing on the harpsichord, Aveline was joined by her father, who informed her that Gérald Blanc requested her presence at the warehouse. Having received a new weapon, Aveline set out to protect the family business from the slander of a business rival. Having journeyed to San Danje, Aveline went to consult the houngan about the disappearing slaves. Aveline and Élise Lafleur set out to infiltrate the fort. With her investigation in the Louisiana Bayou having been largely fruitless, Aveline returned to Gérald Blanc and thought up a plan with him to lure governor Antonio de Ulloa out of La Balize. After inciting a riot, Aveline was advised to destroy a Spanish ship in an attempt to draw out Antonio de Ulloa. With Spanish governor Antonio de Ulloa finally leaving La Balize, Aveline set up an ambush to intercept him, on Agaté's orders.

Having deciphered the map she was given by Antonio de Ulloa, Aveline went to the docks to start her journey to Mexico. Aveline reached the camp in Mexico and began her investigation into the conditions that the slaves transported there lived in. Aveline decided to create new weapons, using the materials she could find. Having tailed Rafael Joaquín de Ferrer to a meeting with the camp's overseer, Aveline eavesdropped on their conversation to find out more about the Templars' true purpose there. Aveline questioned the runaway slave she had rescued and gained more information about her mother, who had been stationed at the camp. Following a trail of clues left behind by her mother, Aveline explored an underwater cave system not far from the work site.

Aveline returned home from her journey to Mexico, and was greeted by Gérald Blanc, who informed her of the changes that had taken place in New Orleans. Upon losing the recruiter in a chase, Aveline aimed to infiltrate the barracks that the man had escaped to. Having journeyed to the Louisiana Bayou, Aveline arrived at Agaté's hideout to warn him of Vázquez's bribed soldiers. Aveline went to her smuggler friends, Élise Lafleur and Roussillon, to warn them of the soldiers bribed by the Templar Vázquez. Aveline met up with Élise Lafleur and Roussillon, ready to plunder the supply ship they had caused to run aground. Aveline returned to Mexico to ascertain whether her mother was safe, as well as retrieve the second part of the ancient artifact.

Aveline returned to the de Grandpré manor, where she checked in on her sick father. Following this, her stepmother, Madeleine de L'Isle, asked Aveline in confidence to escort a slave to safety. Aveline met with her smuggler friends Élise Lafleur and Roussillon, where she asked them for help in escorting the escaped slave, George. Aveline met with Gérald Blanc, in the hopes that he might have information that could help her track down the Templar, Diego Vázquez.

Aveline went to New York to find Officer Davidson, a Templar who would be able to provide more insight into the identity of the Company Man.

Following her trip to New York, Aveline returned home to confront the Company Man, whom she now knew to be her own stepmother, Madeleine de L'Isle. After confronting her stepmother Madeleine de L'Isle, who had turned out to be Louisiana's head Templar, Aveline traveled to the Louisiana Bayou to seek Agaté's counsel and test her faith in the Brotherhood. Aveline returned from her confrontation with Agaté to meet with Madeleine de L'Isle in the Saint Louis Cathedral, where she was to be inducted into the Templar Order. Aveline triggered an Erudito hack, causing the Animus to reveal information that wasn't supposed to be seen.