DC's Legends of Tomorrow - Season 4 Episode 3 Dancing Queen A roaring rewind.
Overview: When the Legends discover a fugitive is hiding in 1970’s London, they realize he is part of a gang that is targeting the British Monarchy. Trying to stop the gang, they realize someone from the Legends must infiltrate them. Surprising everyone, Ray is the one to gain their trust after he is put through a series of tests with help from Sara and Rory. Meanwhile, Gary shows Nate the ropes at the Time Bureau, but it turns out to be anything other than an ordinary day at the office.