In which a vigilant sergeant-at-arms orchestrates the security of a foreboding state prison, while a young man bearing mysterious credentials navigates its sombre courtyards and gothic chambers to gain access to a distinguished captive. Within the ancient walls, a languid officer, lounging amidst the prison's austere surroundings, dispenses gossip and touches of gallantry, revealing the interplay of duty and delicate affections that stir even in the shadow of captivity.