Yorkshire, 1874. Annie Quaintain (Jessica Raine) is turfed out of home when her schoolmaster husband’s death leaves her widowed and penniless. Shunned by society, and with no family to turn to, Annie is desperate for a place for her and her children, Martha (Amy James-Kelly) and George (Sam Bottomley), to stay. When she hears of jobs going in Culverdale Valley, where an enormous viaduct is being built, Annie, Martha and George have no choice but to set off for the promise of a new life in the vast expanse of the Yorkshire dales. Their journey takes them to a remote shanty town in the middle of a valley, the home to a community of navvies. A town called Jericho. Jericho is rough and ready, bustling with life and a wild, carnival-like atmosphere. But life there is tough, and Annie wonders how she’ll make ends meet. She manages to find a roof for her family, but at a price - she’ll be forced to take in grubby and rowdy navvy workmen as lodgers. It won’t be easy, but Annie needs to make as much money as she possibly can to provide for her children and get their lives back on track. Handsome and enigmatic navvy Johnny Jackson (Hans Matheson) returns to his native Yorkshire from Africa and soon finds work on the gang building the viaduct. But before long Johnny makes fierce enemies with a violent-tempered navvy on his gang. Fearing for his safety, Johnny is forced to find new lodgings and arrives, bloody-faced, on Annie’s doorstep. She agrees to take in this dashing stranger, but is unaware of the consequences it will have. Annie and Johnny aren’t the only new arrivals in Jericho. Ralph Coates (Clarke Peters), an experienced African-American railwayman is in town, hired as foreman of the next stretch of the line. Seeing Annie’s struggle, Coates helps her out with a few provisions, but is there a motive behind his act of kindness? Coates is a quiet bystander in this small navvy town, but it soon transpires he might not be all he seems. The viaduct is the vision of Charles Blackwood (Daniel Blackwood). His plan is to join two different railway networks separated by the valley, but Charles needs to raise money for the project to proceed. He gathers a group of investors, and is surprised when Isabella Lambton (Jeany Spark), a figure from his past, arrives amongst them. What could she possibly want after all this time, and can Charles forget old wounds in the name of business? Back at the viaduct, the navvies prepare to blast for the foundations of the viaduct. But what they find in the bottom of the blast-pit sets off a chain of events that will threaten the future of the viaduct for Charles, and jeopardise the new life that Annie, Martha and George are anxious to forge. In need of protection, Annie desperately looks to Johnny and Coates for help. But with secrets of their own to protect, will they be her saviour or her undoing?