For over a decade, more than 10,000 engineers, technicians, and construction workers race to build a brand-new subterranean railroad under London— the Elizabeth Line—London's new Underground and known as Crossrail until February 2016. One of Europe's biggest engineering projects, the construction teams confront immense challenges, from building platforms and concourses the size of aircraft carriers hidden under London's busiest shopping venue, Oxford Street, to designing, outfitting, and testing a fleet of 70 new high-speed trains from scratch in just two years. Facing delays and cost overruns worsened by the pandemic, the engineers and technicians race to create ten new stations, learn to operate the new trains, and test out new 13-mile twin tunnels under London. Drawing on more than 1,500 hours of footage, NOVA provides intimate glimpses of the challenges, setbacks, and ingenious solutions that lead to ultimate success as the Queen finally opens the Elizabeth Line on May 24, 2022.