Sophia, the princess of Gardania, is the daughter of Queen Isabella and King Reginald. However, after a car accident (set up by Dame Devin) that kills her parents, baby Sophia was brought to Miss Willows by the royal dog. Now, Sophia is known as Blair Willows, a regular girl who lives in a slum of the kingdom of Gardania. She works as a café waitress to earn her family money. She lives with her adoptive mother, who is ill, and her adopted sister, Emily, who loves watching the annual Princess Procession, a televised event where princesses and Lady Royals (princesses' advisers) from different kingdoms arrive in Gardania to attend Princess Charm School. The Princess Charm School's aim is to teach princesses and lady royals how to fulfill their princess potential. Every year, there is a lottery in which a commoner's name is chosen and if they graduate, they can be chosen as a Lady Royal.
After Emily enters Blair's name several times in the lottery, her name is picked out and almost immediately, Blair is taken to the Princess Charm School. She meets a dog named Prince who seems to recognize her somehow, and she is given a tour by the Headmistress Privet. Later, Blair receives her school uniform from a sprite named Grace, who is her personal assistant. She bumps into Delancy, the future princess of Gardania, who acts mean towards Blair as she doesn't think Blair deserves to be at the school because she is a commoner.
Blair also meets two princesses, Isla and Hadley, who become her friends. They support her even when Delancy and her mother and Blair's teacher, Dame Devin, are rude to Blair. During a dance lesson, Blair pairs up with a prince named Nicholas, and the two get along well. During another lesson, Dame Devin notices that Blair resembles the queen, who was killed in the car crash with the rest of the royal family, and recognizes her as Queen Isabella's daughter, Princess Sophia (who was already suspected to still be alive). She is shocked and from that day onwards, tries everything she can to get Blair kicked out of school. When looking through the palace one day, Blair and her friends make a connection between the date of the car crash and the date Blair was left on her adoptive mother's doorstep and they realise that Blair is the lost princess of Gardania. Delancy overhears them and realises that her mother is plotting something bad.
Later on, they have Manner Lessons, and Dame Devin announces plans for her daughter that is to be crowned soon to clear the slum area in Gardania and make way for skyscrapers and parks. Blair is horrified by this and argues that she is one of those people living in the slums and they would not be able to find a place to stay. Dame Devin then tells her to leave so that she could pack up with her family and move someplace else. Upset, she does so. But she changes her mind and is determined to prove that she is the rightful heir.
Blair and her friends need to find Gardania's magical crown in order to prove she is the lost princess, as the crown will light up on her head if she is the true heir. Unfortunately, Dame Devin frames them for stealing her jewellery, and they are banned from attending the coronation, where they will be crowned and graduate. Luckily, Delancy offers to help them as she does not want her mother to do anything bad to Gardenia when she is crowned, and gives them a map that will lead them to the crown.
While searching in the palace where Dame Devin and Delancy live, they are caught and Dame Devin plans to leave them trapped through the coronation so that they would miss being crowned. They need a code to get out of the basement they are trapped in, so Blair hooks up her phone to the keypad at the door. Isla remembers the notes played when Dame Devin keyed in the code and figures out which buttons to press. Delancy tries to buy the girls some time and thankfully Blair arrives just in time to stop Delancy being crowned, Delancy gives her the crown. Blair is crowned and it lights up because she is the rightful heir and her uniform is transformed into a dazzling gown.
Dame Devin, out of anger towards Delancy's actions, accidentally admits that she had killed the queen and king so that Delancy could rule one day, and before she could cover up her mistake, she is taken away by the royal guards.
Blair gives a speech to her new subjects and picks a Lady Royal - Delancy. When Delancy asks why she had been picked since she had been treating Blair horribly, Blair explains that she would not have been crowned without her help. Delancy is then crowned Lady Royal of Gardania. At the graduation party, Blair meets Nicholas again and the two dance together, as Isla becomes the DJ for the party, and her mother and sister arrive at the party and are told that they would be living in the palace with Blair.
Blair is a very kind, sweet, clever and hardworking girl, as she is shown working at Café Gardania. She has a lovely and caring personality and believes that people cannot make you feel inferior unless you think so. Despite the fact that she is a teenager, she takes good care of her ill mom and her sister. Also, she has great sense of humour as seen when she tries to top Prince Nicholas in speaking politely. She is a little shy and isn't overconfident. She is also rather clumsy, however with help from Miss Privet she became graceful and elegant. She is also very intelligent, learning things very quickly, and even remembering her true identity Princess Sophia.
Blair is 17 years old, with pale skin, blue eyes, and long blonde hair.
For work, Blair had her hair in a bun and secured with a pink ribbon. Her top was a white button-up blouse with short, puffy sleeves, along with a short pink skirt. She also wore a turquoise apron, white, frilly, ankle-socks, and pink high-heels.
Official School Uniform
The School Uniform Blair wears in Princess Charm School was a white shirt, a blue vest, and a pink tie. The Uniform also a pink and blue plaid skirt, and white socks as well as pink shoes similar to the high heels she wears to work.
When Blair was taking special classes with Miss Privet during the training montage song On Top of the World, she wore a lovely, long magenta dress with magenta gloves. she also wears magenta open toed sandals with heels, similar to the shoes she wears when she becomes her true alias Princess Sophia. Princess Victoria from Barbie: The Princess & The Popstar wore the same exact dress.
When Blair Hadley and Isla found thier uniforms destroyed by Wickellia by order of Dame Devin, they create new uniforms with the help Grace, Caprice, and Harmony. Blair's new customized uniform is a white shirt (the same one from the original), a blue tie and a pink plaid jacket similar to the pink plaid skirt on the original uniform. She also wore a gold belt, a pink skirt, pink socks, and pink shoes.
On the day of Graduation and the Coronation Ceremony, Blair graduates and becomes her true alias Princess Sophia. She transforms and wears a beautiful, royal, pretty in pink, jeweled princess gown.She also wears a pretty pink necklace with a crown and lovely pink open toed sandals with gold bows and heels. She even wears Gardania's Magical Crown.
- "I'm so sorry!"
- "I'm like a burp in a symphony.
- "Sure, I can do anything she can do!"
- "No! No one can make you feel inferior not without your consent!"
- (to Emily and Miss Willows)"Emily! Mom!
- (to Prince Nicholas)"I kind swain, am Blair, maiden of Gardania, Honored above all to be welcomed into your swaininess."
- (to Dame Devin) "How? They're like me, They don't have Money! They can't just pick up and move!"
- "I am making a claim to the throne because I am Princess Sophia, daughter of Queen Isabella."
- "Hello. I'm just a regular girl, but I think Headmistress Privet is right when she said every girl has princess potential. It is an honor to be your princess.
- "It would be an incredible privilege if my Lady Royal could be Delancy."
- (Delancy: "But...Blair Why Me? I was horrible to you.) I wouldn't be wearing this crown without your help. Will you accept? (Delancy: I would be honored, your highness.)
- "There's a princess in every girl."
- She's the fourth princess to be initially unaware of her identity as a princess.
- Rapunzel was the first.
- Rosella was the second.
- Merliah was the third.
- Lumina was the fifth.
- However, unlike the other four princesses, Blair ultimately never got to meet her biological parents, as they both died when she was just a baby.
- She has many similarities with Princess Rosella, as they are not only both unaware of their princess status, but they are also adapt to their new environment, constantly being judged by Dame Devin and Queen Ariana respectively and have a love interest (Prince Nicholas and Prince Antonio respectively).
- She has an adopted family like Lumina. They have been unaware of being a princess and had at least one relative as an antagonist.
- Her biological mother was Queen Isabella. In the 12 Dancing Princesses, there was also a deceased queen named Isabella. They each had a daughter named Blair.
- During the On Top of the World, Princess Sophia wore a beautiful long magenta dress. Princess Victoria wore the exact same dress in Barbie The Princess & the Popstar, Seymour Crider wore the same dress as well, only it was light blue.
- She is the second princess to have a relative as the main antagonist, the first being Princess Genevieve and the third being Princess Lumina. She is also the first to have two relatives as antagonists one being reformed (Delancy), the other being the main antagonist (Dame Devin) respectively.
- From her appearance in the portrait, it can be deduced that she was about a year old when there was an accident.