A 1930s British summer Bank Holiday starts at midday on Saturday with a rush for the trains to the seaside. Doreen and Milly are off to a beauty contest, Geoffrey and Catherine are having an illicit weekend in the Grand Hotel and May and the kids are set for a more straightforward holiday of sea, sand, and pub. Meanwhile, the manager and performers on the pier are praying for rain.

Agnes "Astra" Huston, a fortune teller at a run-down fair, is found strangled in her bedroom. As the police question five suspects, their interactions with her are shown in flashbacks from their point of view.

Working in Dr. Cranley's laboratory, scientist Jack Griffin was always given the latitude to conduct some of his own experiments. His sudden departure, however, has Cranley's daughter Flora worried about him. Griffin has taken a room at the nearby Lion's Head Inn, hoping to reverse an experiment he conducted on himself that made him invisible. But the experimental drug has also warped his mind, making him aggressive and dangerous. He's prepared to do whatever it takes to restore his appearance.