Ecchan is an adult woman with long dark-blonde hair, brown eyes, and typically wears a red sweater. Her past includes a romantic relationship with Yuri during high school, sharing their first kiss. Years later, Ecchan receives a wedding invitation revealing Yuri is marrying a man, sparking bitterness and anger.

At Yuri's wedding, Ecchan meets Aya, who also had a prior romantic relationship with Yuri during junior college. They bond over their shared history and unresolved feelings regarding Yuri. Following the ceremony, a drunken evening fueled by mutual frustration and sadness over the marriage leads Ecchan and Aya into an encounter that gradually blossoms into a genuine romantic relationship.

This new relationship with Aya marks Ecchan's transition from lingering pain over her past with Yuri towards emotional openness. Her dynamic with Aya evolves from shared vulnerability into a committed partnership, signaling personal growth.