The lives of the adventurer mercenaries sometimes take strange and dangerous paths that lead them to participate in wars, make them compete with intriguing wizards, and introduce them to seductive sorceresses. But no one could have predicted the path that would lead Fafhrd and the Gray Mouser to a fantastic adventure on the shores of Nehwon Sea and finally through an invisible door that gave them access to a different world. No one could have foreseen the terrible battles with evil creatures and hateful gods that Fafhrd and the Gray Mouser face in their search for the castle called Niebla.