Fabuła serialu rozpoczyna się 25 lat po wydarzeniach przedstawionych w filmie pt. Legion, tuż po katastroficznej wojnie pomiędzy armią aniołów i ludźmi, która zupełnie zmieniła otaczający świat. Głównym bohaterem jest Alex Lannen (Christopher Egan), młody buntowniczy żołnierz, który odkrywa, że może być jedyną nadzieją na ratunek świata.

Catherine Black is a world-famous neurologist at the state-of-the-art medical institution known as "The Cube". Catherine is brilliant, beautiful, and at the top of her game, though she's hiding a secret of her own: she's bipolar. Each week, the doctors on staff attempt to unravel the mysteries of the brain and are constantly challenged by cases never-before-seen on television. The medical stories are moving, bizarre and a visual feast. The personal stories are riveting. The patients have rare, highly visual, often hallucinogenic and startling conditions, which we’ll see through their eyes as Catherine diagnoses and treats them.

A tale of vengeance set amid Oslo's brutal hierarchy of corruption. The story follows Sonny Lofthus, an escaped convict: an opioid addict who can't recall his past, on the run from the law toward an unknown truth.