Across continents and decades, five brilliant friends make earth-shattering discoveries as the laws of science unravel and an existential threat emerges.

One night in his near-empty tower block in contemporary London, Adam has a chance encounter with a mysterious neighbor Harry, which punctures the rhythm of his everyday life. As a relationship develops between them, Adam is preoccupied with memories of the past and finds himself drawn back to the suburban town where he grew up, and the childhood home where his parents appear to be living, just as they were on the day they died, 30 years before.