This spiky, disturbing animation from South Korean film-maker Yeon Sang-ho owes a little to William Golding's Lord of the Flies; the school classroom it depicts looks the way Golding's castaway island might look if the grownups had never arrived and the feral children were left alone to evolve and refine their brutality over centuries. Kyung-min (Oh Jung-se) is a bespectacled professional who makes contact with failed writer Jong-suk (Yang Ik-june) to talk about their school days, revealed in flashback when, as unpopular kids known as "pigs", they were picked on by the swaggering bullies, known as "dogs". They then relied on a deeply disturbed and violent boy, Chul, to take on these tyrants on their behalf. The "dogs" were policed by a higher prefectorial elite of slightly older boys, to whom the juniors bowed with chilling deference. A strangely gripping and upsetting movie.