Klaudia Huusko is the Finnish exchange student who comes to live in the Kahns household for the school year in Twisted. It seems that all the Rosewood boys are infatuated with her curvy physique and Scandinavian appearance. Her knowledge of English appears to be very weak; when she speaks in broken sentences she often uses Finnish words in place of simple English ones. However, it is later revealed to Aria alone that she is quite capable of speaking in perfect English and is a fraud, when Klaudia threatens to steal Noel away from her.
Klaudia is a slim and curvy teenage girl, with blonde hair and light blue eyes. She often reveals her cleavage and shows off her legs in both school uniform and regular outfits. She attracts positive attention from guys and slightly negative attention from girls, especially Aria.
When Klaudia first arrives in Rosewood, she befriends Aria at the welcoming party the Kahns throw for her. Their shared love for European music and Aria's cultural knowledge makes her relatable to Klaudia. However, when Aria and Klaudia go to a ski gear store together, Aria spies Klaudia's phone outside the dressing room and sees her and Noel's name appearing in Klaudia's text messages with her Finnish friend Tanja. The texts are in Finnish, so Aria has to translate them to find that Klaudia thinks Aria is a troll, and Noel deserves better - as in herself.
So, Aria becomes distant towards Klaudia, and when Aria tries to have sex with Noel at the ski resort, Klaudia bangs down the hotel room door to sabotage the meeting. Noel gives into Klaudia's wants, rather than his girlfriend's desires. Aria shares her concern that Klaudia is trying to break them up and get Noel for herself, but Noel understands Aria to be jealous. After skiing, the three Kahn brothers and Aria go to the jacuzzi, and Klaudia arrives, strips down to nothing, and climbs into the pool. Aria freaks out, screams, and runs away. Noel catches up with her, scolding her for her cultural insensitivity, but Aria protests that Klaudia is being slutty by any cultural standards and is trying to get with him. Noel leaves Aria to go back to the pool to comfort Klaudia.
The next day, Aria tries to make amends by sharing a ski lift with Klaudia and apologizing to her. That is when Klaudia turns on her, tells her in perfect English that she intends to "F*ck her boyfriend tonight", then attempts to knock Aria off the lift. Aria's instincts are faster, and she pushes Klaudia off, fracturing several of her bones, landing Klaudia in the hospital. Noel is suspicious of Klaudia's fall and interrogates Aria, who is vague about what went down. Noel decides to stay longer at the resort in order to stay with Klaudia at the hospital, but Aria has to go, and she takes the bus back to Rosewood alone. Before she leaves, though, when Klaudia is alone with Aria, Klaudia reveals that she thinks she is about to have her way with Noel, giving her the finger, and Aria feels defeated, no longer sure about the status of her relationship with Noel.
In Ruthless, Klaudia and Noel Kahn begin to date after he breaks up with Aria. She is in several of Aria's classes and has become good friends with Naomi Zeigler, Riley Wolfe, and Kate Randall. Klaudia and Aria are partnered for an art history project. In trying to figure out when to discuss the project Klaudia meets Ezra Fitz, who comes back from New York to see Aria. The two are talking in a bookstore/café and the blonde comes to see Aria on the wrong day. It doesn't seem like an accident, for Klaudia had earlier noticed Aria reading a manuscript of Ezra's first novel. She flatters him and claims that she's a big fan of his work. He gives her his manuscript to read, irritating Aria and giving Klaudia another victory over the girl.
Aria and Klaudia meet at the same place a couple of days later. At Aria's request, Klaudia drops her fake dialect and tells her that she doesn't feel like doing her half of the report. When Aria refuses to do all the work, she threatens to tell Noel and Ezra that she pushed her off the ski lift. In turn, Aria tells Klaudia that she'll out her innocent foreign student act to the men. At the school's afterparty for the Macbeth play, Aria catches Ezra making out with Klaudia. By this time, she and Noel are over and he apparently wants her out of his home, claiming that she is crazy.
In Burned, it's said that she was having visa issues and didn't go on the cruise.
In Vicious, she attends Emily's fake funeral. Hanna does not invite Klaudia to her wedding.