The Bard's Tale Wiki

Spell points (occasionally called spell energy) signify the amount of magical power a spellcaster possesses. Casting a spell will cost a certain number of spell points. A spellcaster cannot invoke a spell that requires more points than he has at the time.

Unlike hit points, spell points regenerate naturally, though slowly, when a spellcaster is outside during daytime.

Spell points can also be replenished for gold at Roscoe's Energy Emporium.

Though rare, some dungeons have energy fields that regenerate spell points.