Tears to Tiara - Season 1 Episode 12 Threat of the Empire
Overview: When Riannon is captured by Gaius, Arthur is desperate to save her but Arawn persuades him to wait until they have more information. As such Arawn uses meditation to locate Riannon and check on her safety. Meanwhile, the captive Riannon is making herself useful by healing and feeding the Imperial troops. She is surprised by Taliesin being at the camp, and eventually with Arawn and Taliesin's help, she manages to escape.