After five gruelling days of competition, it's the final of Child Genius 2019. From the hundreds who applied to take part, only five formidably talented children remain. Each one has chosen a specialist subject, which they'll be tested on with degree-level questions. The topics are epidemiology, eukaryotic cell biology, cryptoanalysis, the periodic table, and the physics of black holes. Three contestants will be eliminated, leaving just the top two, who are set to face off in a head-to-head quick-fire round. Who will walk away with the Child Genius trophy?