Prader-Willi syndrome leaves people with a genetic hunger switch stuck permanently on, and this film follows a small group of British individuals living with it day to day. The condition traces to a fault on chromosome 15, first described by Swiss researchers in 1956, and its cause is unusual: whether someone develops the syndrome depends on which parent's copy of the gene is missing, since only the paternal copy is normally active and the maternal one stays silent. When that paternal contribution is absent, the syndrome affects roughly 1 in 25,000 to 1 in 10,000 births. The film sits with families managing constant food-seeking behavior that no diet or willpower fixes, showing the practical measures households use, from locked cupboards to strict routines, alongside the emotional toll on parents and siblings. It also draws the genetic line to Angelman syndrome, the mirror-image disorder that results when the maternal copy of the same region is missing instead, giving the condition a scientific context beyond the individual stories it centers.