The anime follows a salaryman who has a chance meeting with a girl named Ai on the train. They begin to meet every Monday on the train, with the man serving as her bodyguard on the crowded commute while they chat. (Source: ANN)

Despite their distinctive personalities, Souma Shiki, Hayate Ichikura, Shun Futami, and Takayuki Mima all have one thing in common: though naturally clumsy, the four disguise their embarrassment from tiny slip-ups by maintaining a composed demeanor. However, it is actually the guys' airheaded natures that makes the girls' hearts throb. No matter what happens in their daily lives, the boys do their best not to lose their cool!

Away from home for 10 years, Azuma Kazuki had no idea what was awaiting him upon his return. He certainly did not expect to be attacked by dozens of heavily armed people and taken as their prisoner. Fortunately, Azuma's stay in captivity is short. Wielding a strange sentient weapon—known as Bubuki—upon her right arm, his childhood friend, Kogane Asabuki, rescues him. After escaping, Azuma learns that he too has the power to control Bubuki. Together with his new companions, he must revive the Buranki titan named Oubu, that sleeps somewhere deep underground. With this knowledge and purpose, a new path to unearth the truths behind the Buranki opens before Azuma.

After graduating from high school, Mai Kawai's top priority was to find a job with a stable income to avoid turning out like her father. However, despite having taken a variety of civil service exams, she was faced with a harsh reality: nearly every institute denied her entry. The only place that accepted her was a police academy, which she reluctantly joined. Even now that she is an actual police officer, the world continues to be cruel to Mai. Due to her profession, she unexpectedly receives constant criticism from disgruntled citizens. Disheartened by the hostile treatment, she decides to submit a letter of resignation after just a few months of employment. But on the same day Mai chooses to quit, she meets Seiko Fuji—the former ace of the Criminal Affairs Division who is assigned as her new instructor. Finding her new coworker to be enchanting, Mai delays leaving and gives her uninspiring job a second chance.