An adaptation from Cherie Priest's novel, an example of "steampunk" science-fiction, which incorporates futuristic innovations into a Victorian setting, Priest's novel is set in an alternate version of 1880s Seattle, where the city has been walled in and a toxic gas has turned many of its remaining residents into "Rotters," more commonly known as zombies. A young widow hunts for her teen son in the Seattle underworld, while dealing with airship pirates, a criminal overlord and heavily armed refugees.