Hiroshi Tanaka, the perpetually unemployed and lazy but oddly endearing young man instantly recognizable by his enormous afro, is now thirty-one years old. Having gone through high school, dropping out, moving to Tokyo, wandering Japan, and searching for happiness, he has finally reached the biggest milestone yet: marriage. The series begins right after Tanaka proposes to his girlfriend, Nanako Yamada, a twenty-nine-year-old aspiring manga artist with a blunt and practical personality. Together, they leave behind the ramshackle guesthouse life and step into the daunting world of wedding preparations, in-law politics, and the terrifying reality of wedding costs.

The setting shifts from the carefree coastal town of Miura to the more mundane but no less chaotic spaces of rented apartments, wedding venues, and the homes of relatives. Tanaka, who has spent his entire adult life avoiding responsibility and obsessing over trivial pleasures, must now navigate a series of profoundly adult challenges. The narrative follows his efforts to win over Nanako's intimidating father, his panic upon learning that a wedding can cost three hundred thousand yen, and his baffled attempts to understand why anyone would spend that much on a single day. His solution is to compare wedding planning to choosing a brothel, a metaphor that somehow makes perfect sense to him and his equally clueless male friends.

As the story progresses, Tanaka and Nanako marry, and the focus shifts to the next phase of their life together: parenthood. Nanako becomes pregnant, and Tanaka is forced to confront the reality of becoming a father. The couple navigates the ups and downs of pregnancy, the birth of their daughter Emma, and the sleep-deprived, chaotic early months of child-rearing. Tanaka struggles with the loss of intimacy in the marriage, the constant mess, and the overwhelming responsibility, all while trying to maintain his signature slacker attitude. The series also follows the lives of Tanaka's long-time friends from his high school boxing club and his coworkers at the tunnel construction company, each facing their own romantic and professional turning points.

A notable feature of the series is its unflinching incorporation of real-world events. The COVID-19 pandemic arrives midway through the story, and Tanaka and Nanako must deal with mask shortages, lockdowns, and the stress of isolation while caring for a newborn. The humor remains grounded in Tanaka's crude, childish, yet surprisingly insightful observations about life, sex, marriage, and money. Over the course of its ten volumes, the series documents the messiness of starting a family, the ridiculousness of social expectations, and the quiet moments of genuine affection that make the struggle worthwhile, all while keeping the core comedy rooted in Tanaka's inability to ever truly grow up. The story concludes with Emma taking her first steps and Tanaka, now a father, looking back on the whirlwind of the past few years with a mix of exhaustion and contentment.