Tsuruya Hitohiro is a 24-year-old salaryman with no girlfriend and few distinguishing qualities, whose only source of stress relief is fishing alone at sea on weekends. His solitary peace is shattered when he encounters Harusawa Matsuri, a loud and flashy gal with pink hair, decorative nails, and a bikini top, who is struggling on a fishing boat. Other fishermen point her to Tsuruya as the most experienced person on board, forcing the reserved man into the role of teaching her fishing from scratch. After a day of instruction that ends with her catching a sea bream, Tsuruya returns home to meticulously prepare and cook the fish, a ritual of quiet satisfaction. Meanwhile, Harusawa attempts to cook her own catch but burns it completely.

The story immediately complicates when Harusawa transfers to Tsuruya's workplace as the sudden new employee. She is revealed to be the daughter of the company president, and an office memorandum warns everyone that any advances toward her will result in termination. Harusawa immediately recognizes Tsuruya, pulls him into a private room, and blackmails him into continuing her lessons by threatening to tell her father he saw her exposed. She forces him to agree to teach her not only how to fish but also how to properly prepare and cook the catch, launching an ongoing arrangement that blends informative instruction with workplace comedy.

The narrative follows a consistent rhythm that alternates between fishing expeditions on Tokyo Bay and detailed cooking sessions, often at each other's apartments. The fishing sequences provide thorough explanations of techniques, gear, fish behavior, and seasonal considerations, while the cooking halves meticulously cover cleaning, filleting, grilling, and serving. These informational passages are balanced with romantic comedy beats, awkward physical comedy such as fishing hooks catching on clothing or Tsuruya accidentally grabbing Harusawa under inappropriate circumstances, and the growing but unacknowledged tension between them. Harusawa proves to be more than a stereotypical gal, revealing spontaneous kindness when she insists on praying over the fish they catch, genuine passion for learning, and hidden depths including a hobby for late night street racing. Tsuruya, despite his shy and reserved nature, finds his composure repeatedly tested as Harusawa pushes into his personal space, his apartment, and his carefully structured routines. The supporting cast includes Harusawa's rambunctious younger siblings who provide obstacles to any private moments, jealous coworkers who eye the presidents daughter, and the veteran fishermen who serve as a chorus commenting on the unlikely pair.

The central conflict revolves around Tsuruya trying to maintain his peaceful fishing hobby and ordinary work life while being dragged into elaborate teaching sessions by a woman who both exhausts and fascinates him. Harusawa pursues her goal of learning to catch and cook fish properly, but her true motivations increasingly seem tied to spending time with Tsuruya himself. The series uses fishing and cooking primarily as vehicles for slow burn character development and fan service comedy, while the workplace setting adds stakes to their relationship due to her fathers threatened retaliation. Each chapter typically follows a structure of a new fishing lesson, a return to someones home for cooking instruction, and an ending that inches their relationship forward, whether through shared meals, accidental intimacy, or Harusawa teasing Tsuruya out of his shell.