I just wondered around for a while waiting for one Doc Jr or Marty to chime in with a hint after turning the hints all the way up but while I was waiting, the scene played. Just start wandering around the lowest part of the screen and it should trigger.
\ | /SUN "For Peace and Justice!"
-( )-KNIGHT "A Solider in Blazing Armor!"
/ | \POWER! "Solar Knight!"
BUILD UP! "In the Name of the Sun, I will destroy you!"