Tomoko Okano, daughter of the Foreman Mr. Okano, resides in the same coastal region as protagonist Mankichi Togawa. Initially embodying a Spoiled Sweet Ojou archetype, her affluent upbringing starkly contrasts Mankichi’s impoverished fishing village roots. Their first meeting occurs during a rocky shore boat incident, where Mankichi and his friend Rappa attempt her rescue. Though Mankichi typically considers love a weakness, he becomes instantly infatuated with Tomoko. This compels him to trespass on her family’s property after facing maternal punishment for wrecking his boat during the rescue, knocking on her window to initiate contact.

A notable divergence exists between manga and anime regarding Tomoko’s physical state. The manga depicts her as an Ill Girl reliant on a wheelchair during early appearances, but after being temporarily written out, she returns later with restored mobility. Conversely, the anime portrays her as healthy from introduction. Her father’s past actions fuel central conflict: Years earlier, he abandoned Mankichi’s father during a deadly shipwreck when others refused to help. This history echoes when Mr. Okano later sends Mankichi into peril to save Tomoko—from vengeful escaped convicts in the manga or wild dog-encircled mountain hut in the anime. Mankichi’s mother explicitly condemns this as a Uriah Gambit, paralleling his father’s demise.

Tomoko confesses her feelings to Mankichi via a letter he receives. Their evolving relationship culminates in a shared Big Damn Kiss. As Mankichi transitions from junior high to young adulthood, Tomoko represents a pivotal emotional connection that challenges his initial convictions about vulnerability and relationships.