When Maude Horton receives a letter from the British Admiralty informing her of her younger sister's death, her world is shattered. Bold and daring, Constance had run away from her life in Victorian London two years prior, disguising herself as a boy to board the Makepeace, an expedition vessel bound for the Arctic's unexplored Northwest Passage. The admiralty claims Constance's death was a tragic accident, but Maude knows when she is being deceived. Armed with Constance's diary from her time at sea and a fiery desire for justice, Maude sets her sights on the Makepeace's former scientist, Edison Stowe, a greedy and manipulative man who she suspects had a hand in her sister's death. When she learns he has a new venture, a travel company that escorts spectators across the country to witness popular public hangings, Maude decides to join the latest tour, determined to extract the truth from Stowe and avenge her sister--no matter the risk to herself.