In episode 7 "An Expanding World," the elements of summer are intensified by a broken air conditioner—a mundane annoyance that confronts the Yuzaki couple, Tsukasa and Nasa, with a sweltering heatwave. Nasa puts his handyman skills to work and remedies the situation by purchasing and installing a new air conditioner with remarkable efficiency.

Their mission to combat the heatwave leads them to a hardware rental shop, where they encounter Nakiri, Nasa's acquaintance from middle school. The long-standing camaraderie between Nasa and Nakiri seems to spark a rare flicker of jealousy in Tsukasa, though it quickly fizzles out when she realizes Nakiri's deep affection for his machines.

The Yuzakis play a game of temperature adjustment with their new cooling device, swinging between extreme settings and stumbling into a comedy of errors. They painstakingly strive to find the perfect balance, ultimately settling for a slight tweak in temperature.

The episode concludes with Nasa sharing his admiration for married life with Nakiri. While his description is romantic, it paints an endearing picture of his and Tsukasa's life together.