Mordec and the Hidden Hand continues the gripping adventures of Mordec the (now fifteen-year-old) Viking, his friend Gus, and Lily, the young English Queen. While returning from Italy on a slow ship captained by a woman with an all-girl crew, they incur the wrath and enmity of the Black Monks led by the wicked Abbot Alonso de Llama. Then their ship is raided - by fellow Vikings!