After failing with an army of rats, X.A.N.A. attempts a similar tactic using hornets. Meanwhile, Ulrich gets a letter from Yumi saying that she loves him. He's not quite sure how to respond, so he avoids talking to her about it. Jeremie and Odd find out about the note, but don't find out who wrote it. Ulrich tells them not to tell Yumi.
After learning about the hornets and X.A.N.A.'s control over them, the group heads for the factory. Ulrich talks to Yumi about the note and that tells her that he feels the same way, only to find out that it was Sissi who wrote it. On Lyoko, Ulrich's reaction to the discovery leaves his performance lacking as the hornets move on the school. One deactivated tower and a return to the past later, Yumi and Ulrich stop Sissi's scheme before enacted. Leading to Sissi's embarassment.
This episode contain examples of:
- Bait-and-Switch: In his and Odd's room, as Odd patches Kiwi up, Ulrich pulls Yumi aside to talk to her. He starts by saying "I have something to tell you." Yumi says she does, too, before launching into a rumor Odd unintentionally spread about Emily being in love with Jim.
- Big "WHAT?!": Ulrich unleashes one when he skims the contents of the letter Sissi (under the guise of Yumi) sent him. Later, as Jeremie's machine that is distracting the hornets dies from the battery running out of juice, after the genius announces it, Ulrich unleashes another one.
- Big Word Shout: As they are chased through the sewer and are cornered, Jeremie tugs Odd into the sewer water, yelling "Jump!", leaving the genius's scooter and the wildcard's skateboard behind. Later, Jeremie, Odd, and Yumi all yell for Ulrich to "HURRY UP" when the hornets start coming after him.
- Diving Save: Yumi performs one to save Ulrich from being stung by XANA-possessed hornets.
- Heroic BSoD: Ulrich enters one after the revelation that Sissi sent the love letter, pretending to be Yumi. First he sulks in his and Odd's room, then he stands frozen on Lyoko until the end of the mission.
- Hive Mind: A literal example, as well as how XANA controls the bee swarms. XANA seems to have gotten the idea from the previous episode, where he used rats to evacuate the school.
- Impairment Shot: Inverted. Ulrich gets hit in the face with a soccer ball. As he comes back to consciousness, Jim, Jeremie, and Odd bounce in and out of focus for a few seconds.
- Love Letter Lunacy: Sissi sends one to Ulrich, pretending to be Yumi, confusing him.
- Scary Stinging Swarm: Kiwi and a professional bee exterminator are injured trying to handle them, even before Xana's tampering is detected.
- Violence Discretion Shot: We don't see Kiwi getting stung, as he does his business and looks up, barking menacingly at the incoming swarm, then coming to Ulrich injured. Later on, Odd is confronted by Emily as she found out about the rumor he inadvertently started about her being in love with Jim. Before he could defend himself, Odd stutters and stammers, before the camera cuts to Ulrich and Jeremie, who wince at Emily punching their friend's cheek.
- You Are Better Than You Think You Are: Yumi gives one to Ulrich when he is in his Heroic BSoD, snapping him out of his stupor and kicking butt on Lyoko.
