Physicist Jim Al-Khalili spends two episodes chasing down the biggest and smallest questions in physics: what everything is, and what nothing is. The first half looks outward, tracing how mathematics and observation built our picture of the universe, from the scale of galaxies down to the equations that describe them. The second half goes the opposite direction, into the physics of the subatomic world, where empty space turns out to be far from empty. Al-Khalili talks with physicists working at both ends of this scale and uses studio demonstrations and graphics to make abstract concepts, like vacuum energy and the mathematics of spacetime, visible rather than just described. The throughline is a single claim he builds toward across both episodes: that everything in existence may have emerged from nothing, a proposition modern cosmology takes seriously rather than treats as a paradox. It is a two-part science program in the familiar BBC-style expository mode, presenter-led, well-illustrated, and aimed at making cosmology and quantum physics legible to a general audience.