Miss Caline Bustier is a teacher at Collège Françoise Dupont.
In “Ladybug & Cat Noir (Origins - Part 1)”, when Miss Bustier noticed Nino sitting the back with his headphones on, she told him to move to the front row. Once the entire class was seated, she introduces herself to her new students. After class was over, she noticed Ivan getting angry at Kim and sent him to the principal’s office.
In “Stoneheart (Origins - Part 2)”, during attendance, Miss Bustier was amused when Adrien shouts "present" loudly upon hearing his name be called. When she calls for Ivan, she was shocked when Stoneheart bursts into the classroom instead. Later, while watching the news with her students, she was shocked when Hawk Moth announced himself and demands that Ladybug and Cat Noir surrender their Miraculouses, but when Ladybug refuses and vows to protect the people of Paris, Miss Bustier cheers.
In “Mr. Pigeon”, Miss Bustier was seen next to Mr. Damocles as he announces Gabriel Agreste's derby hat contest to her students.
In “Lady Wifi”, Miss Bustier compliments her students, as most of them did well on their last assignment. She then gives them their homework and asks Alya to deliver Marinette's. The next day, when Marinette comes late to class and shouts once hearing from Nino that Alya was suspended, Miss Bustier told her to be discrete if she comes in late. However, when Marinette shouts again after hearing that Alya thought Chloé was Ladybug, she angrily sends her to the principal's office. However, when Lady Wifi appears, she instructs her students to go home for their safety, but not before giving them homework.
In “Dark Cupid”, Miss Bustier talked to the class about how most fairy tales end with the prince breaking a spell by kissing the princess and asks why, to which Rose replies that only love conquers hate. When Max begins to point out that sort of logic is only in 87% of fairy tales, Miss Bustier cuts him off. She notices that Adrien was writing something rather than listening and asks him what she said, but when Adrien repeats what she'd told the class, she's impressed. Once class ends, she reminds her students to finish Sleeping Beauty.
In “Darkblade”, she announces that Chloé was running for class representative and gives her students until the end of lunch to decide whether or not they want to be a candidate. When the end of lunch arrives and no one volunteers, Miss Bustier almost declares Chloé the class representative, but then Marinette says that she'd like to run. Delighted, Miss Bustier reminds her to develop her campaign and have a speech prepared. The next day, Miss Bustier reveals that by majority vote, Marinette has won.
In “Pixelator”, Miss Bustier took the class to Le Grand Paris hotel for a work experience field trip. When she notices Ivan and Alix having a pillow fight and reminds the class that the trip was worth a huge portion of their grade to get them to stop. Miss Bustier then notices that Marinette and Alya are not on the mayor's list, but Chloé then gives her father another paper explaining Marinette and Alya's jobs. The mayor told Alya her job and almost told Marinette hers when Jagged Stone comes into the hotel. After the ordeal was taken care of, Miss Bustier reminds the mayor that he never gave Marinette her job, which the mayor then says was gopher duty.
In “Reflekta”, Miss Bustier poses with her students for a class photo, though when Chloé starts to complain about where she was put, she told her to behave herself. When Juleka asks to use the bathroom while the photographer gets some batteries, Miss Bustier allows her to go but told her to hurry back. Mr. Damocles reminds her that the photographer said no one is to move, but Miss Bustier explains that it was an emergency. She also allows Sabrina to go to the bathroom.
In “Despair Bear”, Miss Bustier and her class were listening to Tom Dupain’s cooking lesson until the fire alarm goes off. She tells her students to exit the classroom quietly and single file.
In "Robostus". she looked on in horror as the titular villain took Max.
In “Zombizou”, it’s Miss Bustier birthday. Everyone in her class gives her a gift - everyone except Chloé, who forgot. When she discovers that Chloé sabotaged the gift Marinette made her, unlike her students, she was more forgiving. Then, asks to speak to her outside, and Marinette, thinking that she’s in trouble, gets angry and becomes vulnerable for akumatization. However, before the akuma can infect her, Miss Bustier assures Marinette that she isn’t in trouble and only wants her to set a good example for her classmates by forgiving Chloé, making Marinette’s negative emotions go away. Marinette insists that Chloé was the worst person she’s ever known, but Miss Bustier reminds her that there are people worst that Chloé living in Paris and shares her belief that people like Chloé are capable of great things but need a positive example in order to better themselves. After she and Marinette come to an understanding, Miss Bustier notices the akuma and fearfully tries to shoo it away, unaware that her being afraid makes her vulnerable for akumatization. When the akuma infects her, she attempts to resist, but ultimately gives in when Hawk Moth says that he wants to give her the power to spread love and compassion, turning her into Zombizou.
Zombizou enters her classroom and tells her students that from now on, everyone will hug, kiss, and feel the love. She blew a kiss at Chloé, but Chloé uses Sabrina as a human shield and the kiss infects her instead. Zombizou prepared to blow another kiss, but Ladybug bursts in and stops her before she can. She fights her until an infected Sabrina, Ivan, and Mylène come back into the classroom. She decides to leave Ladybug to them and goes from classroom to classroom looking for Chloé, all while blowing multiple kisses at the students and staff.
Zombizou eventually catches up to Ladybug, Cat Noir, and Chloé on top of the Eiffel Tower and demands that Ladybug hand over her Miraculous and Chloé. When Ladybug goes to fight her, Zombizou points out that she’s all alone as everyone else has already been infected and tells her to accept her love and hand over her Miraculous. But instead, Ladybug uses her Lucky Charm item to wipe the lipstick off Zombziou's face. When she attempts to reapply, Ladybug grabs the lipstick from her and breaks it, freeing the akuma and turning Zombizou back into Miss Bustier, who then expresses remorse over letting her negative emotions get the better of her and hurting a lot of people. However, when Chloé admits that the whole ordeal was her fault and apologizes, she accepts the apology and hugs her. The next day, Miss Bustier enters her classroom and says that they'll start the day by giving nice compliments to their neighbors.
In "Frightningale", she took part in Clara Nightningale's new music video.
In "Malediktator", when Chloé presents a video of herself dressed as Queen Bee to the class, Miss Bustier asks Chloé why she made her assignment about herself. When the class starts making fun of Chloé, Miss Bustier tells them to calm down and then tells Chloé that class isn’t over when she angrily exits.
In “Catalyst (Heroes' Day - Part 1)”, Miss Bustier believes Lila when she says on a video chat that she’s in the Kingdom of Achu. She asks her what she’ll be doing for Heroes Day and thanks her on behalf of Earth when Lila claims to be working on a pollution-reduction project. After Lila hangs up, Miss Bustier tells her students that though it may be hard to live up to Lila’s standards, there are other ways to do good deeds. She then goes around and asks everyone what good deeds they are planning on doing. Later, when a bunch of scarlet akumas invade the school, Miss Bustier was seen shooing some away and reminds everyone that there’s a hero in every one of them.
In “Mayura (Heroes' Day - Part 2)”, Miss Bustier is delighted upon seeing that Ladybug and Cat Noir are alive and well.
In “Chameleon”, Miss Bustier announces to the class that Lila has returned. She believes Lila when she claims to have tinnitus and need a front row seat, therefore when Marinette complains about having to sit in the back due to the new seating arrangement, Miss Bustier reminds her that she doesn’t have any trouble hearing or seeing. Enraged by Lila’s lies, Marinette was almost akumatized, but Miss Bustier calms her down when she tells the class to open their textbooks. After lunch break, when the class returns, Miss Bustier does attendance. When Marinette fails to answer despite calling her name three times, Miss Bustier believes that she may have hearing problems after all and asks her to move to the front row next to Lila. When Lila claims to have been cured of her tinnitus and no longer need a front row seat, Miss Bustier allows several of her students to move back to their original seats.
In “Gamer 2.0”, Miss Bustier collects her students’ tests and later was seen talking to Mr. Damocles when she along with several other Parisians are brought into Gamer 2.0’s game. As her akumatized identity, Zombizou fights Horrificator and easily defeats her. After Gamer 2.0’s defeat, Miss Bustier and the others are freed.
In “Oblivio”, after Alya and Nino explain that they were akumatized because they were embarrassed at being caught playing Super Penguino, Miss Bustier forgives them but reminds them that games should be played at home rather than school field trips.
In "Ladybug", Ms. Bustier told everyone that they did will on the Mock Exams, but became surprised that Marinette had the test answers when she heard Marinette accuse Lila of sabotage Ms. Bustier sent them both to Principal Damocles' office. When the squabble ends with Marinette's expulsion it leaves her saddened to the point of being akumatized again into Zombizou but was deakumatized when Nathalie lost her powers.
In "Timetagger", Ms. Bustier was one of the many people the titular villain sent into past altering the future.
In "Startrain", Ms. Bustier was taking her class on a field trip to see Big Ben in London and upon seeing Chloe go the opposite train car, she points her to the other direction until being informed by Sabrina that Chloe's father arranged for her to sit in first class. During the train ride she sat next to Nathaniel reading a book however their trip took a turn when Max's mother got akumatized into Startrain sending everyone into space. After Ladybug and Cat Noir, she followed the heroine's instructions and led everyone to the back of the train once the titular villain was defeated everyone was put safely on the ground then, resumed their class trip.In "Kwamibuster", she was in the middle of teacher class a history lesson until Ms. Bustier saw some of her students being distracted by a noise below but quickly regained their attention.