Three individuals facing life’s challenges form an unusual relationship when they meet Kita-kun, a charming young man who accepts them all. Unable to handle their feelings alone, they agree to share him equally and start living together.

Senagaki Isaku will be a first-year high school student starting in spring. Her grandfather is the third head of the Senagaki group, a yakuza organization, so she is feared by those around her. However, starting from spring, she hopes to make normal friends and normally fall in love. She is admitted into a high school further from her hometown, however, the overprotective young head of the Senagaki group, Utou Keiya, (26 years old) falsifies his age and enters the school with her through a backdoor admission…?! Keiya proclaims that love is too early for her although Isaku is perfectly ready. In truth, she has held an unrequited love for Keiya for quite some time.

Chiyomi Horikiri (Ai Iinuma) is a warm hearted high school student. She is a member of her school's basketball team. She stays bright even in a bit complicated family composition. Her boyfriend is Hiroyuki Minami (Yusei Yagi). One day, Hiroyuki Minami suddenly shrinks in size to only 15 cm. in height. He can easily fit in the palm of someone's hand. He appears in front of his girlfriend Chiyomi Horikiri.

本剧改编自同名漫画，讲述了高三那年夏天，宝安慰哭泣的大进，大进难忘此事，从福冈追到东京的大学来找宝。原本大进不明白那份心情是什么，但渐渐地对宝产生情愫。某天迎新聚餐，大进喝醉了，被宝带回公寓照顾，大进趁着醉意告白了。第二天早上，宝吻了吓得一脸苍白的大进，说“接吻感觉不糟，所以跟你交往”。后来两人长时间相处，宝想回去自己的住处！？

Taishin has moved to Tokyo from his hometown of Fukuoka in order to reunite with Takara, a stranger who had consoled him in his grief the year prior. However, despite finally getting a chance to express his gratitude to Takara at college, he is given the cold shoulder! But Taishin, undeterred, decides to pursue Takara anyway, and Takara finds himself becoming more and more enchanted by Taishin’s straightforward and earnest gaze.

凤来高中3年D班的班主任九条里奈，是放弃贴近时代、贴近学生的化学教师。毕业典礼那天被“班里的某个学生”推下去，然后时光倒流，站在讲台上，眼前看到的是一年后杀害自己的“30名嫌疑人”。她下定“决心”，颠覆教室、人生，冒着生命危险挑战面对学生。