"Hitorijime My Hero" is a romance anime series centered around the lives of its main characters, exploring themes of love, protection, and personal growth. The narrative primarily revolves around Masahiro Setagawa, a high school student who has been bullied for years and finds himself entangled with local delinquents. His life takes a turn when he encounters Kousuke Ooshiba, a former delinquent turned math teacher, who steps in to protect him. Kousuke, known as the "Bear Killer" for his past reputation, becomes a mentor and protector to Masahiro, gradually forming a bond that evolves into a romantic relationship.

Parallel to this, the story introduces Asaya Hasekura, a childhood friend of Masahiro, and Kensuke Ooshiba, Kousuke's younger brother. Asaya harbors feelings for Masahiro, creating a complex dynamic between the characters. Kensuke, on the other hand, is a high school student who becomes romantically involved with Asaya, adding another layer to the interconnected relationships. The series delves into the challenges and emotional struggles faced by each character as they navigate their feelings and relationships.

The plot explores the growth of Masahiro as he learns to stand up for himself and confront his past, while Kousuke grapples with his protective instincts and the responsibilities of his role as a teacher. Asaya and Kensuke's relationship develops amidst misunderstandings and personal insecurities, highlighting the complexities of young love. The series balances moments of lighthearted humor with deeper emotional arcs, portraying the characters' journeys toward self-acceptance and mutual understanding.

Through its focus on the intertwining lives of its characters, "Hitorijime My Hero" presents a narrative that emphasizes the importance of trust, communication, and emotional support in relationships. The story unfolds through a mix of tender moments and conflicts, offering a portrayal of romance that is both heartfelt and grounded in the characters' personal struggles.