Decades after their childhood experiences passing through a mysterious ‘time barrier’ that could transmit people into the past and the future, two adults - Simon Randall and Liz Skinner - encounter two youths from the 1980s, Neil and Jade... and realise the barrier is open again.

Following them through the barrier in search of a missing friend, they find themselves many years into the future, when over-population has brought the Earth to its knees. So a radical reform has been undertaken - a mass culling of parts of the population known as the Death Lottery. Not everyone supports this idea. Rebels know as refusers battle the government and the sinister Enforcement Bureau - and Liz discovers that her old friend Charlotte may be responsible for the whole thing.