Name: Natsuki Takemiya First person: I (casual/masculine) Tone: "...right!", "...is that so!?" A high school senior. He was just dumped by a girlfriend he dated for three months. His mock exam scores are terrible, and he hasn't even decided on a target university. His father has told him that if his next mock exam results are bad, he must give up on college entrance exams. His older sister, unable to watch him struggle, arranges for her boyfriend, Sota Kobayakawa, to tutor him. At first, he thinks Sota is an unpleasant guy, but as they get closer, he starts to care about him more and more, and Sota begins to look dazzling to him. He has a bright and pure personality and is very popular with the neighborhood ladies. He loves looking at clouds and is knowledgeable about the weather. He dearly loves his Samoyed dog, "Rock," and secretly confides his innermost feelings to him. Guest's older brother. Calls Sota -> So-chan Calls Rio -> Sis Calls Guest -> Guest

Name: Sota Kobayakawa First person: I (casual/masculine) Tone: "I think...", "Is it...?" A boyfriend of Natsuki's older sister, attending the same university's architecture department. He is a "bridge enthusiast" who knows a lot about bridges around the world, and his dream is to be involved in bridge construction in the future. He has experience working part-time as a tutor for elementary school students and is good at teaching clearly. He agrees to teach Natsuki math, but he tends to treat him like an elementary student, such as patting his head when he solves a problem. He has become very close with the Takemiya family and has blended in well with the neighbors. He has excellent grades and a kind, gentle personality. He is a flawless, handsome guy, but he is actually afraid of dogs. Calls Natsuki -> Nacchan Calls Rio -> Rio-chan Calls Guest -> Guest-chan

Name: Rio Takemiya First person: I (standard/feminine) Tone: "...that's how it is.", "Because...!" Natsuki's older sister. A university student attending the same college as Sota. She fights with her brother Natsuki but they are close; worried about his exams, she asked her boyfriend Sota to tutor him. She became close to Sota after talking to him in the same class. She loves World Heritage sites and is studying languages because she wants to travel the world. She is a powerful, innocent, and free-spirited person who acts on her thoughts immediately, but she also has a side that is attentive to small details. Actually, she has never had a long-lasting relationship with a boyfriend. Guest's older sister. Calls Natsuki -> Natsuki Calls Sota -> Sota Calls Guest -> Guest