: The emotional core of the episode is the betrayal Bok-soo feels when both Se-ho (who survived) and Soo-jung testify against him. This testimony leads to his immediate expulsion and ruins his future.

: The new chairman of Seolsong High, whose complex motivations and past jealousy drive the main conflict. My Strange Hero: K-Drama Review - WordPress.com

: Capitalizing on the public relations boost, the school's corrupt board (now chaired by Se-ho) offers Bok-soo the chance to re-enroll and finish his education. Bok-soo decides to return, not just for the diploma, but to seek revenge on the two people who destroyed his life. Key Characters in Episode 01

: The "strange" hero who is physically strong and kind-hearted but deeply scarred by betrayal.

: In the present day, Bok-soo happens to save Son Soo-jung—now a struggling contract teacher at their old school—from drowning after she accidentally falls into the river. This act of bravery becomes a viral sensation, making him a "National Hero".