"Rent-A-Girlfriend" centers on Kazuya Kinoshita, a college student who, after being dumped by his girlfriend Mami Nanami, turns to a rental girlfriend service to cope with his loneliness. Through the app, he meets Chizuru Mizuhara, a charming and professional rental girlfriend who initially appears to be the perfect companion. However, Kazuya’s impulsive decision to continue renting her services leads to a series of increasingly complicated situations.

As the story progresses, Kazuya and Chizuru’s relationship evolves beyond the transactional nature of their initial encounters. After Kazuya’s grandmother falls ill, he lies to her by claiming Chizuru is his real girlfriend, prompting Chizuru to play along. This deception spirals into a web of lies involving their families and friends, forcing the two to maintain the façade of a romantic relationship. Despite their initial reluctance, Kazuya and Chizuru begin to develop genuine feelings for each other, though their pride, insecurities, and misunderstandings often hinder their ability to express these emotions.

The narrative introduces several other key characters who add layers of complexity to the story. Ruka Sarashina, another rental girlfriend, becomes infatuated with Kazuya and actively pursues him, creating tension in his relationship with Chizuru. Sumi Sakurasawa, a shy and reserved rental girlfriend, provides a contrast to the more assertive personalities in the series, offering moments of quiet introspection and growth. Mami Nanami, Kazuya’s ex-girlfriend, re-enters his life, harboring unresolved feelings and a manipulative streak that further complicates the dynamics between the characters.

The series explores themes of self-worth, emotional vulnerability, and the blurred lines between genuine affection and performative relationships. Kazuya’s journey is marked by his struggle to mature and confront his insecurities, while Chizuru grapples with her own emotional barriers and the pressures of maintaining her dual identity as a rental girlfriend and an aspiring actress. The interactions between the characters are driven by a mix of humor, drama, and occasional moments of heartfelt sincerity, creating a narrative that balances lighthearted comedy with deeper emotional undertones.