On the surface, high school student Koyuki Koyun Hikawa seems unapproachable and terrifying to most other students. In reality, Koyun is just insecure and prone to overthinking due to her uncomfortable experiences in middle school. However, her chance encounter with two boys in school—Minato Amamiya and Youta Hino—sparks a change in her. Like her friend Miki Azumi, the boys are never afraid to approach Koyun and see her for who she really is. Although Koyun starts spending more time with Miki, Minato, and Youta, she finds herself torn between her newfound bliss and her fear of getting too attached to others. Meanwhile, each of her friends quietly struggles with their own challenges. But as the new friend group continues to navigate high school together, Koyun and the others start to break out of their shells and enjoy their adolescence to the fullest.

Technology, science, and industry—this is 1969 Tokyo, and there is no better time to be alive! But a shadow looms quietly around every corner: Invaders have infiltrated the populace, and nobody knows who or what they are. Only the members of the top-secret agency AEGIS know of their existence. Covertly fighting the enemy is their job, but only those with the ability to open Gates to another world can truly defeat them. Within AEGIS is a specialized task force known as the Gate Keepers. Composed of extraordinary individuals with a variety of Gate-related abilities, they are the only ones who can save humanity from the vicious Invaders plaguing the planet. Shun Ukiya is an average high school student who lives with his widowed mother and little sister. While on his way home from school one day, he comes across a group of Invaders heading toward his house. In a desperate plight to save his family, Shun discovers he possesses the ability to open a Gate, allowing him to harness massive amounts of energy. With his newfound ability exposed, he catches the attention of AEGIS, and particularly the interest of one of its Gate Keepers, Shun's childhood friend Ruriko Ikusawa.

Seeing everyone else enjoying their youth, socially anxious Renako Amaori is dead set on becoming an extroverted girl. Despite her reclusive past, she changes her appearance, practices conversation, and enrolls in a high school free of anyone that would know her. While she is quickly able to befriend the famous model Mai Ouzuka, after Renako joins her friend group, she realizes pretending to be a completely different person is no easy feat. Soon, Renako and Mai have a heart-to-heart and share their troubles with each other. After the sincere discussion, Renako truly believes they could become best friends. The very next day, however, the unthinkable happens—Mai confesses her love to Renako! Although Renako is not interested in dating, Mai insists the two begin hanging out alternately as friends and a couple, while figuring out which type of relationship suits them better. Determined to create a blissful friendship, Renako tries her best to convince the stubborn Mai. However, Renako herself might have a change of heart as Mai's advances continue to get bolder.

Tsuwabuki is a normal student, though not very social. One day he meets a new transfer student, named Sumomo Akihime, and another girl, both the only members of the gardening club. Tsuwabuki is forced by a teacher to join this club. But then he bumps into a strange guy with dog ears, switching his drink with they guy's by mistake. Drinking it, he is turned in a stuffed animal. The teacher tells him that the only way to turn back to normal is to find the chosen girl and let her catch the seven stardrops. This girl is Sumomo, that accepts to help him, though she's not allowed to know the animal's true identity. (Source: ANN)