S1 · E921 March 202567m9.0

The Mathematics Teacher

Undercover High School

Episode Summary

As Su A recovers in the hospital following the attack during the break-in, Hae Seong and the team uncover the culprit: Lee Jun Ho, the mathematics teacher. When Hae Seong detects his father's notebook missing, he realizes that Seo Myeong Ju orchestrated the break-in. After Lee Jun Ho's arrest and confession, the revelation of the school's grade-rigging scandal throws the institution into chaos. Amid the turmoil, Hae Seong stumbles upon a crucial clue to the final scary story.