Suguru Tsutsui is a Japanese male with black hair and brown eyes, though some sources depict him with gray hair and gray eyes. He embodies extreme duality, experiencing both crippling misfortune and bewildering luck, primarily driven by impulsive choices and prioritizing sexual urges over reason. This flaw manifests when he falsely claims to pass college entrance exams to sleep with his girlfriend, Hazuki Yoshimura, who promised intimacy as a reward. Upon discovering the lie, she terminates their relationship.

To atone and reclaim Hazuki, Suguru relocates to the city for focused exam preparation. His apartment sits above a strip club, where he unexpectedly gains a female roommate after meeting her on a train and later finding her undressing in his home. This arrangement severely disrupts his academic discipline.

Despite being characterized as unreliable, undisciplined, lecherous, and unintelligent, Suguru attracts numerous women like Yukiko and Ai, fostering a persistent harem dynamic. His romantic attention shifts toward the elusive Urara, whose shyness makes her uniquely challenging to pursue. His existence revolves around chaotic misunderstandings and self-sabotaging comedic mishaps, frequently escalating into compromising scenarios with women.

Documented media shows no substantive growth or resolution of his core flaws. His narrative persists as a cycle of navigating chaos from his actions, the complications of his living situation, and the tension between academic goals and relentless romantic distractions.