Jarvis Stringer lives in a crumbling schoolhouse overlooking a tube line, compiling his obsessive, secret history of London's Underground. His presence and his strange house draw a band of misfits into his orbit: young Alice, who has run away from her husband and baby; Tom, the busker who rescues her; truant Jasper who gets his kicks on the tube; and mysterious Axel, whose dark secret later casts a shadow over all of their lives. Dispossessed and outcast, those who come to inhabit Jarvis' schoolhouse are gradually brought closer together in violent and unforeseen ways by London's forbidding and dangerous Underground.