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One spell.  Tenser had just one spell, preserved magically in his mind.  A combination of arcane components would activate the spell and it would leave his mind.  He could speak the same words again, make the same gestures, but there would be no more magic associated with them until he had rested and re-prepared his spell the next day.

For any magic-user, no matter how powerful, there was something a little frightening about casting that last spell of the day.  Leaving yourself defenseless to the world until you had your spell or spells back.  Tenser had felt that way many times in the rough neighborhoods of the City of Greyhawk.  Here in the dungeons of Castle Greyhawk, he expected to feel infinitely more powerless.

But that didn't matter.  His friends needed to be protected.  He cast his spell.

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