Undercover High School S01E07 - The 24th Anniversary of Byeongmun High School

Hae-sung is caught off guard when he recognises Soo-ah's childhood name, Bong-ja, which stirs memories of his first love and distracts him from his focus. Despite the emotional turmoil, Hae-sung pushes forward with the mission to uncover the secrets behind the third ghost story. However, a missing key component forces Soo-ah to join the mission despite Hae-sung's strong opposition to her involvement.