Hiram Walker

Hiram is a young man who was born into bondage on a plantation in Virginia. He has a photographic memory but is unable to remember his mother. Hiram's mother was sold by his father, the plantation owner, to a different plantation when Hiram was nine. When Hiram does access a memory of his mother performing a water dance, he finds that he is able to use the energy generated by this memory to activate a power called “Conduction”—when he comes into contact with water and draws on his memory, he is able to travel from one place to another instantaneously. He uses this power to escape from the plantation and enters the world of the Underground, joining the fight against slavery and attempting to free those left behind at the plantation.

Howell Walker

Howell is Hiram’s father and the master of Lockless plantation, where Hiram is bound at the beginning of the book. Howell sold Hiram’s mother, Rose, to a different plantation when Hiram was nine years old.

Thena

Thena is an enslaved woman at Lockless plantation who helps to raise Hiram. Hiram is able to free her toward the end of the book.

Sophia

Sophia is enslaved at Lockless plantation. She and Hiram try to run away together, but they are captured. Sophia is forced to live with Howell's brother, Nathaniel (Hiram's uncle) and eventually becomes pregnant by him. Eventually, Hiram and Sofia raise the baby, Caroline, together.

Corinne Quinn

Corinne is the wealthiest woman in the county and was formerly engaged to Hiram’s half-brother, Maynard. She is secretly involved with the Underground, and she asks Hiram to use his power of conduction to help free slaves. She later acquires Sophia so that Sophia and Hiram can be together.

Moses (Harriet Tubman)

Harriet Tubman, nicknamed Moses by the enslaved characters in the novel, shares the power of conduction with Hiram. She uses this power to help free slaves via the Underground, and she teaches Hiram how to control and access his power.