During a fierce storm, a train carrying seventy-five people is hurled into the Firth of Tay when the bridge it is crossing collapses. Everyone on board is killed. It is the night of 28th December 1879. Long before the incident, Andrew Mason, a jute mill owner and a reluctant shareholder in the venture had been sceptical and worried. Constructing the proposed, single track railway bridge over the yawning gap of the Tay Estuary seemed an almost impossible task. The story is told showing a catalogue of mismanagement, poor workmanship and use of inferior materials, leading to dramatic incidents and fatal accidents plaguing the workforce. As dreaded by Andrew, after only 18 months, the disaster occurs. He has been a voice in the wilderness and now his worst fears have been realised. His life is full of conflicts and traumas. He has a love affair, a wife addicted to laudanum and Spiritualism and he faces the hostility of his many notable contemporaries in the rapidly growing town of Dundee. Spider's Thread is a work of fiction, but the story of the Tay bridge disaster is real. The tragedy and the lives of the people it touches are vividly brought to life through the eyes of Andrew Mason.