In the late nineteenth century, when Conor Broekhart discovers a conspiracy to overthrow the king, he is branded a traitor, imprisoned, and forced to mine for diamonds under brutal conditions while he plans a daring escape from Little Saltee prison by way of a flying machine that he must design, build, and, hardest of all, trust to carry him to safety.

When the Imagination Station sends time-traveling cousins Patrick and Beth to a ship that is captured by the British during the Revolutionary War, they are befriended by James Forten, a free Black of Philadelphia, and help save the life of an imprisoned boy dying of scurvy. Includes a secret word puzzle.