In Japan in the year 1600, at the dawn of a century-defining civil war, Lord Yoshii Toranaga is fighting for his life as his enemies on the Council of Regents unite against him, when a mysterious European ship is found marooned in a nearby fishing village.

Howard Silk is a lowly cog in a bureaucratic UN agency who is turning the last corner of a life filled with regret when he discovers the agency he works for is guarding a secret: a crossing to a parallel dimension.