Some ruins are invisible. Under the pavements of Paris there lies buried an ancient river, the Bievre. For years, Lucy Frost has walked along these streets, unaware of the water and history under her feet, on her way to clean the apartments of Paris's academic class. As she begins to study and transcribe the inherited notebooks and papers of her great-aunt, a teacher and researcher who disappeared years earlier, she commits to continuing her aunt's youthful research on the Bievre, mining the river's documentary traces in the works of the great chroniclers of Parisian life, uncovering a history of industry: paper mills, dyeing workshops, tanneries, and textile manufacturers - and laundries. She finds resonances of her own labour in the history of the river's laundresses. On stolen time at work, and in her insomniac hours of night writing, she fills notebooks with these woven stories and descriptions of obsolete sites, textiles, cosmologies, and voices, constructing her own forms of relation with the lost. Riverwork unearths not just an urban river but also a philosophy of research and the archive, a politics of hydrology, an ontology of ageing and belatedness, and a consideration of the unrepresented labour of women, past and present. Along the way it brings to life, in pyrotechnic prose, a long-gone Paris and both its domestic workers and its writers.