Mark of the Plague: Blackthorn Key, Book 2

The Black Death is killing people by the thousands, and there's vivid description of its gruesome symptoms and torments, as well as dead bodies. Also, it soon becomes clear that some of the "plague" deaths are actually murder, and there's a race to bring the killers to justice before they strike again. Due to the plague, Londoners have been ordered to kill all their animals, so Christopher's constantly challenged to keep Bridget safe. Over the course of the story, the kids suffer beatings, stabbings, poisonings, and broken bones; adult characters perish in an exploding house, and another is lynched by a mob. Pistols and swords are brandished. The villains take the teens captive and threaten to torture them.

Readers may begin to suspect a future romance between Christopher and Sally, but it's only the faintest glimmer for the characters themselves, who tend to be distracted with other matters.

There's no plumbing in this era, so there are many references to pee, poop, and raw sewage in the streets. Pigeon poop is valued for producing saltpeter, an ingredient in gunpowder. In one scene, the kids take advantage of the fact that a guard is relieving himself to sneak into a building.

In keeping with the era, people of all ages consume wine and ale. As an apothecary, Christopher makes and administers medications, including "poppy" (opium) to relieve a friend's serious pain, as well as antidotes to poison.

Parents need to know that Mark of the Plague is physicist-turned-author Kevin Sands' follow-up to the much-honored The Blackthorn Key, with its teen protagonists facing new dangers and struggling to solve new mysteries in 1665 London. One mystery: Who is this stranger who seems to be able to cure the bubonic plague that's ravaging the city -- and what's in his medicine? Another: Where (and what) is the mysterious treasure left to 14-year-old Christopher by his late master? As the plot unfolds against a backdrop of the black plague's devastation, the teens suffer beatings, stabbings, poisonings, and more in their efforts to discover and unmask a murderer. Like in Book 1, Mark of the Plague delivers swashbuckling adventure, brain-teasing puzzles, several explosions, and assorted gun-brandishing and sword-wielding. As in Book 1, the narrator gives the recipe for gunpowder. Pee and poop abound, sometimes as part of the pre-plumbing scenery and sometimes as a chemical ingredient. Some characters die, and there are brief gory descriptions of injuries and plague symptoms as well as dead bodies. Also as in Book 1, this installment has a strong moral compass, with frequent but non-preachy messages about friendship, loyalty, kindness, using your brain, and doing the right thing even when you're being strongly pressured to do the wrong one.