On the last day of school, Togger reminisces with Abel and Tanya about the old days: they recall their treasure hunt in the sewer tunnel – nearby, the Year 7's overhear and decide to explore themselves. Togger's on the verge of quitting, so Tanya calls in his uncle – ex pupil Tucker Jenkins, to persuade him to stay for his final year. Meanwhile, everyone is in danger when a bomb is discovered underneath the school.