Heroes of the Lance was a game based on DragonLance: Dragons of Autumn Twilight, utilizing the main characters from the book and letting you play their journey into Xak Tsaroth and confronting the black dragon.
In the book Goldmoon confronts the dragon with the Blue Crystal Staff. Assuming you were lucky enough to have her still alive in your party and the staff still had energy, as soon as you approached the dragon your entire party would immediately be killed.
A quick search didn't reveal any walkthroughs for the game that might tell me how to beat it.