1950s Manhattan: the CIA carries out a covert study of psychoactive drugs. Ad man Ned Sweeney is dosed with MDT-48, and finds his horizons dramatically expand. But how long can he maintain the extraordinary pace of his new life?

Sixty years later, all that Ray Sweeney knows of his grandfather's life is that he committed suicide. But then Ray meets a retired government official, who claims he can illuminate the truth behind Ned's death.

Both a sequel and a prequel to The Dark Fields, which was adapted into the hit movie Limitless, Under the Night explores the seductive power and dangers of unlocking the human mind.