In revolutionary struggle, if you don’t defeat your enemy, your enemy will defeat you. On his return to his hometown – and his wife – to aid the Cultural Revolution, soldier Aijun sees a young woman wandering barefoot along the railway tracks in the warm late-afternoon sun. Her name is Hongmei. From this moment on, an ‘unspeakably beautiful flower’ blooms in Aijun’s heart. As Aijun and Hongmei hurl themselves into their town’s revolutionary struggle, they become inseparable. They spend their days and nights stamping out feudalism, writing pamphlets and attending rallies: they are the engines of history. But soon, their sexual and revolutionary fervour begin to merge, and a crazed new love explodes between them. The party bosses are hugely impressed by the ardour of the pair’s work. Emboldened, the couple build a ‘tunnel of love’ – to further the revolution, of course.