"Mankind will cease to exist at 6pm GMT on 28 March 3256." A computer prediction which threw the world into panic. What to do? Build a starship and take the chosen few to a new home in the stars, Or search for an alternative timestream where mankind goes on forever.

Matt Helm is to captain the last space shuttle carrying passengers to the starship, but his irrepressible desire for Fern Angelus corrupts his sense of duty. He agrees to take part in her time experiments.

Set against a background of passion and longing, Matt's uncanny success with mind projection meets with unforeseen complications. He projects his mind into a future Earth: a world of shallow, extensive seas, mutated trees growing in layers on each other's branches, and strangely evolved animals like snappersnouts, humpers and energy creatures.

Matt's strange visions eventually meet reality when he discovers that the last load of passengers for the starship has been left behind, and he is one of them.