Aria uses all the profits from her selling sugar to invest in new businesses and startups. She uses Baron Burboom as a cover for her identity and uses the alias Investor A.
Anyone who wishes to receive investment or seek console has to go through Baron Burboom as the middle-man. This group includes low-class nobles like barons, merchants, or commoners.
She invests based on the trends she knows will become popular in the future. Though Aria isn't 100% sure which business will become successful in the future.
The twist to this is that... she actually ends up establishing a 3rd power base (does this unknowingly though). The Crown Prince faction, The Noble Faction, and Investor A's faction (Aria hides her name as "Investor A").
Mielle gets increasingly frustrated about Aria and decides she will try to bring Investor A's faction to the Noble faction and invites all the wives of Investor A's faction to the Count's house for a tea party. This is a very strange move because she is a count and some of the invites were given to commoners. Anyone who wasn't too busy accepted the invitation (for curiousity sake). She tries to win them over (but they aren't falling for it). Trying to get them to accept gifts (but they deny them). Aria happens to stumble across them just as Mielle was trying to get them to accept her gift. She joins the tea party and shows off her intellect by engaging on their business topics (since she reviewed all their businesses she knows all about their business). The wives' then invite her to their next business meeting. Mielle leaves in frustation.
Aria ends up joining the business meeting (the businesses supported by investor A hold regular meetings and review which business partners will be good to invest in before telling Investor A. Aria meets the crown prince there as he appears with a different name (Aria confuses the new name with as his real identity). Asher then proposes a business he has planned. He wants to open an academy that would allow anyone to join if they have the talent, it would be paid for by the crown prince and Investor A only has to lend them their name, the business partners of investor A would be given first choice from their best students (so they can gain trained employees for their startup businesses).
At some point Sarah's wedding ceremony is held and Aria goes to give her, her blessings. She sees Asher as is leaving, and meets him in a garden. There he reveals to her he is the crown prince and they have a quick conversation. As Aria is leaving (her face blushing red) Isis catches a glimpse of her face and decides to check out the garden. She notices the crown prince and starts to get worried. Later when Mielle is visiting the duke's mansion Isis orders her to get rid of Aria and hides her some poison. Mielle's headmaid then tells the maid whose been getting bullied by Annie and Jessie to poison Aria's tea. The next day she serves Aria, Jessie and Annie tea as usual but she can't stop fidgetting. Aria notices immediately that something is wrong and takes out her hourglass before telling Annie to drink from her cup. Annie immediately collapses and the maid immediately becomes sorrowful and begs for mercy. She turns the hourglass. Now she pretends to drink from her teacup and collapses. The maid looking ecstatic throughout the entire motion. After Aria collapses, Jessie and Annie immediately run over and call for a doctor, meanwhile the maid flees from the scene.
The maid goes missing and the entire capital and all the servants and guards of the mansion are searching for her whereabouts. Aria helps stir the suspicious onto Mielle's headmaid since she is supervisor. She later adds fuel to the rumor because no one had fled the capital and yet the maid was still somehow able to hide under everyone's noses. The only one capable of sheltering the culprit had to be the headmaid. Later on Asher shows up and tells Aria that he found the maid and gave her a location and said "It's up to you what you do with her". Around this time Asher also hands Aria a bracelet as a protection charm. Aria goes to visit a dirty warehouse and finds the maid cowering in a corner covered in filth. She baits her by telling her if she confesses to the authorities who told her to do it she can help her flee the country and give her enough money to live for the rest of her life. The maid doesn't believe her at first but Aria tells her she can just say she was threatened, and that if she didn't listen her family would be killed. The maid immediately latches onto her only hope. And she confesses the headmaid had told her to poison Aria, that she had no other choice because she was being threatened. Mielle chooses to abandon the maid (she had no other choice or she would take the fall). The maid is to be given a sentence after a court hearing.
I forgot when but Aria also reveals she is Investor A and shocks everyone in the capital.
Around this time Cain starts visiting Aria's room often and it's clear he is looking at Aria like a woman instead of a sister. Aria notices and is disgusted by it but she purposefully leads him on. At some point Cain has an inner monologue about how he used to look down on his father for taking a prostitute as a wife but now he can't help but think he has the same blood running through him because he is attracted to his sister-in-law. On the day of the sentencing the judge asks Aria for the judgement and she requests for the maid to be executed, lest more innocent souls get harmed. As her family was about to head home Aria excuses herself and rendezvous with Asher in an alleyway. Cain secretly followed her and discovers Asher. He quickly gets jeleous. The maid gets beheaded. Mielle stays in her room and cries for days or weeks. At this point all the servants in the count's house look at Mielle with disdain though. When she finally leaves she has taken her noble lady mask off and glares at everyone.
Mielle stops trying to act like a saint and looks at Aria with disdain all the time and forgoes all pleasantries. Later on Mielle tries to approach her only remaining ally in the house, her blood relative and brother Cain. Cain who is powerless to stop Aria from meeting with Asher loses his temper whenever he sees Aria heading out and becomes pretty desperate. This is when Mielle approaches him. She suggests a plan to corner Aria. The plan holding a huge tea party that would involve the wives' of the noble faction. They would make sure there are no witnesses around. The two siblings would then bring the Count up to Aria's room and tell her to come downstairs. Just as Aria is about to reach the staircase on the 3rd floor (her room is on the third floor), Mielle pushes the count down the stairs. The count turns around mid-fall and tries to grab at the air, only to grab Aria's bracelet and the bracelet falls apart, shattering beads all over the floor. He notices Mielle was the one who pushed him down. Mielle then screams for help... when suddenly Asher appears out of thin air, surprising both Aria and Mielle. Asher looks shocked and confused as well but quickly grabs Aria and disappears from the scene.
Aria and the Crown Prince appear at a resturant half a day away by carriage from the capital. Aria tells Asher what happened and they decide to leave evidence that they had never been at the scene by traveling to a foreign country. They would gather eye witness accounts of their travels and leave credit behind the places they visit (parchment with a record of what they owed the establishment along with the time of their visit). This is later used in court when Mielle tries to frame Aria for the assassination of the Count.