S4, E21: When pupils start to go missing from Smallville High, Clark steps in to investigate. All evidence points to the school photographer, who Clark later discovers has created a secret `school' in which he keeps the students hostage so that he can keep reliving the glory days of high school. While Clark tries to free Chloe and the other kidnapped pupils, Lex and Lionel are captured by the Teagues in an effort to find the crystal.