Althea pulled on her silver cloak, raising the hood to cover her head. She fastened a thin veil across her face, hiding her features. With a steady breath, she closed her eyes and cast an illusion across the bedchamber—on the bed, a perfect image of herself lay sleeping, as if she hadn’t moved at all.

When the spell settled, she opened her eyes and lifted her hand in a slow, precise swirl. A faint shimmer formed in the air, widening into a small portal. Her voice dropped to a whisper as ...