Wataru Morooka is a teenage high school student with brown eyes and black hair cut to ear length. Coming from a less affluent background than some peers, this socioeconomic difference fuels social tension. His driving motivation is pursuing a romantic relationship with wealthy, reserved classmate Mai Sakuragi, whom he considers his ideal love interest, during their final summer before college. This goal shapes his actions but faces obstacles from other characters and Mai's demanding schedule.

He becomes romantically involved with multiple female classmates. Tsundere Misa Tanaka initially acts coldly toward him, but her feelings shift after he aids her injured leg and supports her confronting her parents about her future. Their deepening relationship leads to a physical connection. After a breakup, Satomi Kurokawa seeks his comfort, sparking a romantic and physical relationship despite their previous acquaintance. Following rejection by his best friend Kazuya Sakagami, Kurumi Nishina turns to him for solace, resulting in a physical encounter that redirects her affections toward him.

These relationships lead to an unconventional arrangement where Misa, Mai, Kurumi, and Satomi agree to share romantic involvement with him temporarily, pledging to compete for his commitment after graduation without hostility. He demonstrates caring traits, encouraging Misa through her insecurities and supporting her during medical treatment for her leg injury. However, his romantic indecisiveness is clear as he maintains multiple relationships while initially prioritizing Mai.

Societal obstacles due to class differences challenge him, particularly Mai's family's disapproval. Mai eventually defies her family to pursue the relationship, leading to her confinement and his persistent efforts to reach her. She risks disinheritance to be with him.

In later events, his romantic focus shifts toward Misa. He gives her a ring symbolizing commitment, though they temporarily separate after an unresolved argument. Misa attempts to move on by becoming involved with someone resembling him, but he tracks her down, apologizes, and they reconcile. His persistence in repairing their relationship despite other romantic options indicates a prioritization of their bond.

His social circle includes wealthy rival Kenji, who deems him unsuitable for Mai due to economic status and actively obstructs the relationship. Class-based prejudice from Mai's family and Kenji's interference represent ongoing external challenges. Resolution comes through Mai's defiance and his consistent efforts to bridge their social divide.

His character development shows an initial romantic pursuit evolving into complex entanglements, culminating in a choice favoring Misa. His actions reflect both a capacity for emotional support and inconsistency in managing multiple relationships, with his arc concluding in a dedicated partnership.