In 1891, in a world transformed by 1799's Great Disruption--when all of the continents were flung into different time periods--thirteen-year-old Sophia Tims and her friend Theo go in search of Sophia's uncle, Shadrack Elli, Boston's foremost cartologer, who has been kidnapped.

Finding an old map, Gabe and his friends follow clues to a secret chamber beneath San Francisco, where they perform what they think is a friendship ritual before strange events reveal a sinister cult from a parallel realm.

While on vacation in the Bahamas, the Thea sisters stumble across an old pirate map and endeavor to find the treasure, unaware that someone else is also seeking the prize.