It is 3pm on Monday. Emily Smith is summoned to her daughter's school, an elite hothouse where pupils work under exacting standards of grades and behaviour. She is reassured that Olivia isn't in trouble, but the news is even worse - her child is missing.

A minibus carrying the swim team never arrived back from a gala. The police don't know where it has gone and the school's 'no phones' policy means none of the kids has a device. They have vanished.

As time ticks by and fear becomes unbearable, the real danger may not be the kidnapper but someone much closer to home...