Kobato Hasegawa/Plot Overviews

Background
Shortly after birth Kobato and Kodaka's mother had passed away. Due to their father's low interaction with them, Kodaka had taken care of Kobato at a young age thus becoming extremely clingy towards him. 10 years prior to the story Kobato and her family had lived in the town she currently lives in with Kodaka but had to move away due to their father's work.

Hasegawa siblings affair
Kobato is constantly displeased by his brother's tardiness and lack of attention after his involvement in his club and was greatly frustrated when she discovered that he is cooking lunch for another girl other than herself. Eventually, Kobato forced herself inside the Neighbor's Club clubroom and warns Kodaka of prioritizing club activities over her and gets a one-on-one with the girl Kodaka had been mentioning to her before - Maria. However, the following day Kobato announced her membership to the Neighbor's Club, making her the seventh and last member so far to join the said club.

First activities and summer break
In her green days in the Neighbor's Club, Kobato got to write a grotesque story involving her and Kodaka during the medieval times in the club's novel relay activity, going to karaoke, and switched to lighter clothes in time for summer where they went to the pool, which ended in a bad result. After agreeing on going to Sena's beach resort, the Hasegawa siblings were invited to the Kashiwazaki residence and spend an overnight stay where Kobato was chased by a naked Sena after taking a bath. Days later, Kobato along with the other Neighbor's Club members frolic by the beach at Sena's villa, dubbed as a training camp. Sometime later, Kobato went alongside with the club to go to their town's shrine to celebrate the summer festival and gets to wear a yukata with her brother. After playing at the fairs around the shrine's park, the club went lighting fireworks where Yozora's hair was caught on fire while the club could only stare in silence as she walked away.

In the meantime, Sena was "charmed" by Kobato's characteristics, (who bears many similar traits to that of the galgame characters which Sena interacted with) and was soon under the false impression that Kobato was her little sister, much to the latter's fright. While Kobato has an ongoing ruse with Maria, who was being intimately close to her brother and her being a "servant of the light".

Post-summer break
Procrastinating over her summer homework, Kobato turned to her brother for help, where he also asked assistance for the Neighbor's Club and was mostly finished. Sometime later, Maria came to disturb the peaceful days of her and Kodaka at their house where she had an overnight stay. Albeit chagrined, Kobato is shown more lively and playful with Maria around. The following day, the Neighbor's Club had a party at their clubroom where they played the King's Game and Kobato was ordered by 'King' Sena to wear a revealing "bikini armor" during the first round, much to her displeasure.

Trip to Yokoshima Wonderland
Upon Kobato's entry to the clubroom, she is immediately welcomed by an excited Sena who invites her to Yokoshima Wonderland, a famous theme park, where Yozora intervenes and declares that the whole Neighbor's Club will be going instead. During their trip at the park, the club rode the infamous Black Dragon roller coaster, much to their fright; Kobato then went with her brother and Sena to watch a costume show of her favorite show, Kurogane no Necromancer. Before the main show started, Sena intends to get on Kobato's good side by acting knowledgeable about Kobato's favorite show, but this backfired when Kobato points out Sena's ignorance over the details of the show, much to Sena's dismay. At the start of the show, the hostess and her partner wearing a costume of "Astaroth", the show's antagonist, asks the audience for a "hostage" that will receive a prize later on. Sena happily volunteers, but as the hosts mistook her as Kobato's mother, Kobato was instead called to be the hostage. As one of the "hostages" by Astaroth, Kobato, in her Gothic persona, introduces herself to everyone as Leysis and implies to the audience that the Astaroth before them is a fraud, pointing out his demise in the show's first season. Nonetheless, the show ended with no major delays and Kobato receives her prize: an autograph from Kurogane no Necromancer's director along with a distorted drawing of the show's heroine, which Sena took as "garbage". However, after his brother's persuasion, Kobato shyly thanked Sena for her efforts of getting her the autograph and storms off in anxiousness.

After eating lunch, Kodaka and co. went out to try out the different rides in Yokoshima, while Yozora and Sena headed back to the Black Dragon roller coaster to compete. Hours later the gang searches for Sena and Yozora, and found them in an ill condition. Surprisingly, the two girls then vomited on Kodaka, leading them to visit a neighboring hot springs resort to rest and wash up. Afterward, they head back home.

New semester and discussions for the cultural festival
Due to failing to finish her summer work Kobato attends supplementary classes to make up for this - thus is absent from club activities for weeks.

Upon her return, Kobato is immediately greeted by Sena. While discussing their booth for the upcoming school festival, the Neighbor's Club checks on books regarding fortune telling where they discover the nearing date of Kobato's birthday. Knowing this, the Neighbor's Club agrees on throwing Kobato a birthday party, much to the latter's surprise.

Birthday party
While Kobato was reluctant of going to the clubroom, Kodaka entices her and enters the clubroom with Sena firstly greeting Kobato "Happy birthday", much to her fright. This is eventually followed by the other Neighbor's Club members greeting her while in-simultaneously popping their party poppers - leading to awkwardness - much to Kodaka's dismay.

Afterward, the club proceeds with the party and Sena presents Kobato with her birthday cake. Though impressed at first, Kobato gives an unpleasant face when she finds the dolls on top of the cake depicting her and Sena together. Singing a birthday song, Kobato then blows the candles on the cake and eventually, the club dines on the snacks and eventually the cake. Kobato then receives her gifts from her fellow Neighbor's Club members and the party ends.

While going home, Kobato happily holds onto her presents and remarks that she had a great day.