Miyuki Onoda (née Yura), 25, marries Makoto Onoda, with neither having prior sexual experience. Miyuki's striking beauty frequently attracts male attention, causing her significant discomfort due to her deeply shy and easily embarrassed nature. This inherent shyness and naivety make her reserved, especially regarding intimacy.

Living together after marriage, the couple faces early stumbling blocks in physical intimacy due to their mutual inexperience. Despite these challenges, Miyuki shows willingness to explore sexuality within her marriage. She engages in regular "practice" sessions with Makoto as they work to overcome their lack of experience together.

During this time, Miyuki draws support from friends, acquaintances, and educational media. This guidance helps her gradually become more comfortable with intimacy. Her journey shows progression from initial embarrassment towards more active participation in sexual exploration with her spouse, though she consistently retains her characteristically modest disposition.

The live-action film adaptation depicts Miyuki's experiences as a newlywed, continuing to emphasize her transition from complete inexperience towards developing confidence within her marital relationship. Her fundamentally shy personality persists, occasionally resurfacing in moments of embarrassment.