Stuck with a co-pilot, Missy has taken extreme measures. After all, she only needs the Monk's brain to fly his TARDIS. But when Missy and the bodiless Monk end up on different sides of a planetary war, they may need one another to survive.
Missy takes the Monk to Earth to make a point - she can be nice if she wants. In fact, she can save the planet. While the Monk tries to charm the corporate sharks, Missy makes them a better offer. To supply the ultimate warrior.
On the trail of some weapons-grade plutonium, Missy and the Monk visit Renaissance Italy and the house of an elderly Borgia. But someone else is en route to the Tuscan villa with designs on the old man's treasures.