Having narrowly escaped death at the hands of Zoe Hardcastle, The Widow, Entomologist, Aaron Pike, is seconded to Colonel Eric Trantor’s research team, based at The Ark, a vast underground military complex. Aaron knows that he will only see the light of day again when the arachnoids pose no threat to humanity.

Meanwhile, football mad ten-year-old Kyle Fisher is bitten by a huntsman spider while playing on Clapham Common. When he goes into anaphylactic shock, his mother, Helen, calls for an ambulance. A few minutes after the paramedics arrive, a helicopter lands in the park, and soldiers take Kyle away, leaving Helen with no clue as to where they’re taking him. Luckily, one of the parents watching the football game is a human rights lawyer and helps Helen locate her son.

Kyle Fisher is not the only infected patient at The Ark. Jenna Martin, who had a one-night stand with Professor Philip Jackson, is also being studied, and paying the price for her indiscretion, imprisoned in the facility while her body is changing. No one will tell Jenna what is happening to her, or Kyle.

Aaron, Colonel Trantor, and other researchers have to work together to find out more about the arachnoids before Zoe Hardcastle’s two missing children can procreate, increasing the risk of an explosive epidemic.