"Harmony is the Greatest of Virtues" is the second episode of Durarara!!x2 Shou and the twenty-eighth episode overall of the Durarara!! anime.
In the beginning of the episode, two figures, one a tall blond man named Egor and the other a zombie like person, encounter each other in a park in front of Shizuo Heiwajima and Tom Tanaka. The two begin to fight, the blond man takes a briefcase from Tom and Shizuo. Shizuo becomes enraged and uses the park bench he and Tom were sitting on as a baseball bat and launches the two out of the park. Shizuo then goes out looking for another attaché case to replace the one that the blond man broke.
In the chat room, Kanra asks if everyone is liking the new chat room and then proceeds to send a link to a video. When Celty Sturluson gets on she tells everyone that she lost her months pay. Kanra then send a link to a video of Max Sandshelt giving 10 million yen to anyone who would reveal the identity of the headless rider.
In Shinra Kishitani's apartment we see him trapped inside of a sphere of Celty's shadows. He explains everything by taking us back in time, after the end of the last episode Celty goes back home and waits for Shinra to come back. When Shinra gets back home he finds Celty inside a sphere she made out of her shadows, she brings Shinra inside and tells him about how she lost the million yen she had. Shinra tells her that she doesn't have to worry about that. Celty gets a call for a job and heads out but forgets to release Shinra from her shadow.
At the end of class, Mikado Ryuugamine is approached by Aoba and he tells Mikado that he is in the Dollars and that he knows that Mikado is in the Dollars as well because he saw him at the Dollars meet up in front of the Tokyo Hands building. Aoba asks Mikado if he can take him on a tour of Ikebukuro.
Mikado and Anri Sonohara are with Erika Karisawa and Walker Yumasaki in a karaoke bar and they ask them if they can help them with giving Aoba a tour of Ikebukuro. Erika and Walker agree and they start singing karaoke.
Anri then heads out and walks past a tall blond man named Egor. Saika then starts acting up and Shingen Kishitani tells Anri that he knows about Saika. When Anri asks how he knows this, Shingen only gives her his card and tells her to call him is she wants to know. Egor puts his hand on Anri's shoulder, she gets scared and moves away. Egor tells her that he has urgent business to take care of with Shingen. Anri then leaves as Shingen and Egor go back to their private room.
In Izaya's place, Namie Yagiri tells him how she wanted to be at Seiji Yagiri's opening ceremony and tells Izaya that his sisters just started as first year students. Izaya explains that he doesn't like his sisters. Namie is then surprised that he despises anyone other than Shizuo. Izaya tells Namie about his sisters eccentric personalities. Namie asks if they might get bullied because of that. Izaya says that if they get bullied, he'd feel sorry for "them."
Back at Rira, we see Mairu being bullied where she then pounces on one of the bullies and tells her to point out their "leader" and when she points her out, Mairu takes her to the bathroom. After this, the bullies decide to bully her sister and the teacher asks who did this to her desk, in which Aoba then answers that it was Tsukiyama and some girls from another class.
After school, the bullies approach Aoba and ask him why he told on them as he replies to them tauntingly. Then, Tsukiyama's bag catches on fire. After this, Aoba's teacher talks to him about the bullies. When Aoba leaves, Mairu and Kururi approach him and Kururi thanks him by giving him a kiss, Mairu then kisses Aoba as well. Aoba then asks then if they did anything to the bags of the bullies. They say it's a secret.
We fast forward to the part where Shizuo hits Egor with the park bench. Mairu and Kururi find Celty's million yen and Egor bleeding out. Egor asks them is they could take him to Russia Sushi.
Back at Shinra's apartment, we see Haruya Shiki coming into Shinra's apartment.
In order of appearance, excluding the opening song: