Marinette and Adrien plan their first official date, in which Alya and Nino briefly join in. She tries going to the movies and a café, but since she is new to dating, she doesn't know how to act with or around Adrien, instead trying to mimic what the other couples around her are doing. She gets so anxious that she transforms into Ladybug to help the other heroes, who have started going on patrol without her leadership, even if said heroes don't need assistance. The date is postponed when a little girl, who loves to draw, named Maya is akumatized into "The Illustrhater" now being able to draw any object into existence. Ladybug, Cat Noir, Rena Rouge, and Carapace all work together to take down the villain, after which Marinette finally expresses her fears to Adrien. As a precaution, Marinette gives a Ladybug kwagatama to Alya, so that she can access Ladybug's memories, should anything happen to her.

Marinette notices Adrien has a new friend, Sublime Varlette, who is a talented musician and para-athlete. Marinette wants to catch Sublime's attention and make friends with her, but she does so in over-the-top ways that culminate in her breaking Sublime's prosthetic leg on the day of a race tryout. This causes Sublime's mother, Caroline, to be akumatized into "Sublimation", who can make anyone into the best version of themselves as she even tries to do the same thing to Bob Roth after he walked out in disappointment. After a short battle, the Lucky Charm causes Ladybug to realize that she caused everything, so she apologizes to Sublime both as Ladybug and Marinette while advising them not to take Bob Roth as a sponsor. Later, Marinette becomes true friends with Sublime. In the final scene, Sublime's family go to Tomoe Tsurugi to sponsor her. She accepts the sponsorship while secretly having a plan of her own.

Adrien meets with his grandparents – Emilie's parents Lord Emil and Lady Milly Graham de Vanily of Westchestermunster, and Gabriel's parents, the hippies Johnny and Gabrielle Grasette.

Marinette plans an extravagant celebration for her one hundredth kiss with Adrien, forgetting that it falls on the same day as a movie night with her friends.

When it comes to a name for their group, everyone agrees on the name "The Miraculers". Marinette and Adrien find out that their relationship is being publicly tarnished by Vincent Aza who is now a social media influencer under the name "Vincent Secret".

Adrien has no idea what to do with his life after his father's passing. To remedy this, Marinette tries helping him find his passion, but none of her suggestions stick with him.

Marinette and her class plan a concert to thank Mayor Bustier. While rehearsing, Marinette and Adrien go through the latter's old things where Marinette finds a letter from Gabriel explaining his true identity.

Nathaniel illustrates a romance fantasy comic written by Marc, but he doubts it will catch on, especially since his architect mother Shirel wants him to take up more "serious" arts like architecture. Despite encouragement from Marinette (who is sick with the common cold) and her friends, Shirel finds out about his comic and forces him to quit and pulls him out of school.