Penniless Peggin is taken in and given work as a maid by the renowned Ladies of Llangollen, a real-life lesbian couple moving in the literary circles of Byron and Wordsworth. But she is a difficult character and struggles to repay their kindness. Peggin's brother Joe is driven and hard-working, giving all his energies to the building of Thomas Telford's Pontcysyllte Acqueduct, but is tormented by a promise he has failed to keep. Betrayal comes in many forms in this moving tale of the trials of one family over 25 years.