Adrien was at fencing practice where they are trying for new fencers when Marinette shows up and says "I'm looking for Adrien, you know tall, blonde and (while holding her hands at the side in a lovey dovey fashion) super handsome." "(eyes widen in realization) Do you like me Marinette?" Adrien asked, only for Marinette to say "No, I mean YES! I mean..." Only for Adrien to interrupt her with saying "So you do like me, that explains everything. The way you talk, the way you act around me and the love note was from you wasn't it?" "Yessss." Marinette said strained, only for Adrien to say "I'm sorry but I don't love you back." This caused Marinette to be Akumatized.
She had on a pick shirt with a black broken heart on it with puffy sleeves, a red skirt in the form of a rose, green boots (that reached just above her knees) in the form of steams, white gloves with holes on the back of the hand and the palm, she had white wings, she was wearing a red back quiver that was carrying arrows, she was holding a red bow, her hair was messed up and her purse (which was the Akuma object) was now pick with an black broken heart on it
She now calling herself Heartbreak hit someone with the tears she was crying (which were like jets) and then shot an arrow at someone causing them to start crying uncontrollably. Adrien then left and transformed into Noirebug and then arrived at the scene, where she is shoot by jets of tears but she blocks them with her staff while tieing Heartbreak with Noirebug's yo-yo. While Heartbreak got herself free, Noirebug come towards Heartbreak and destroyed her Akuma object with an "Cataclysm!"
Riposte
Adrien told Marinette that "Even though I don't like you the way you like me, we can still be friends." Marinette left happy that Adrien still wanted to be friends with her. Fencing tryouts resumed like normal with a new fencer (Kagami) challenging Adrien and the two fought with it being decided it was a draw since no one saw who won. Even though this was enough to let her in, Kagami was still not happy about the draw (as her mother told her that draws were just as bad as losing) and left unhappily. Adrien would've comforted her but was distracted by his new crush on her. He only snapped out of it when she came after him as an Akuma when she cut his limo in half, causing him to get a broken arm.
She was calling herself Riposte and tried to fence him in a duel but Adrien didn't have a weapon to duel with, causing him to say "How are we suppose to have a proper rematch if I don't have a weapon to duel you with?" This caused her to leave to get a fencing weapon back at the school while saying "Don't go anywhere!" But after she left Adrien did go somewhere, he left to transform which he did. When Riposte came back with the weapon Noirebug immediately tied up the Akuma object with her yo-yo and then pulled it (as with Riposte along with it) towards her and then "Cataclysm!" it.
Adrien told Kagami that "So what if we tied, you're still the best fencer this side of the school. At least in my opinion (while handing her a rose)." She toke the rose while developing a crush of her own on Adrien.