After the High King Artorius' death, Morgen, the Queen Gwenhynfar and some warriors escaped the fall of his fortress Camlann. Pursued by Angle and Saxon raiders, they brought along his treasure. Morgen also carried Artorius' silver dragon ring.
Indiana Jones encountered her on the night of October 31, 1913 (Halloween or Samhain) when he came across "ghostly riders" near Cadbury Castle and somehow travelled through time. The riders were Morgen and company, and Cadbury Castle was in fact Camlann. Earlier, Indy and a friend, Cerdic Sandyford, had discovered an ancient ring buried within a spring. Indy now wore that ring. Morgen noticed the ring and explained the situation to Indy. He saw Artorius' men bury their treasure at a local landmark. Morgen revealed she carried the ring Indy was wearing and said she would hide it where he would find it hundreds of years later. When Indy returned to the present, he and Cerdic dug up the treasure and used it to alleviate the Sandyford family's financial problems.
Morgen described her magical abilities as the "fey power", or "Second Sight". With a touch on Indy's forehead, she made him understand ancient Welsh, her language (while Indy spoke English). She also conjured up illusions of monsters to block pursuing raiders.
Morgen later became known in legend as "Morgan le Fay". Indy noted that she was a villain in legend while in fact she had "fought on the side of good" in reality.
- Young Indiana Jones and the Ghostly Riders
- Indiana Jones and the Dance of the Giants (Mentioned only) (As 'Morgan le Fay')