The 2021 Texas blackout triggered the largest energy crisis in the state's history, leaving millions stranded for days without power and leading to hundreds of deaths. It revealed just how vulnerable the state's power grid had become by going it alone. Back in the 1970s, one utility company sent its workers out under cover of darkness to secretly connect the Texas power grid to the rest of America. And why the rest of the Lone Star State's utility companies worked so hard to stop them.