Maria Testa, better known to Brunetti as the nun who once cared for his mother, turns up at the Commissario's door. Maria has left her nursing convent after the... » 

Maria Testa, better known to Brunetti as the nun who once cared for his mother, turns up at the Commissario's door. Maria has left her nursing convent after the suspicious deaths of five patients. Is she creating fears to justify abandoning her vocation, or is there a more sinister scenario? «