Alan and Julia, married but living apart for four years, are reunited in 1974 when Alan moves from Jamaica to join her in Toronto. Julia is employed as a lab assistant. She has been in Toronto since 1970 and is working to set up a home and gain the financial stability required to bring her family to Canada. Their reunion is joyous at first, steeped in excitement and the rediscovery of their romantic passion. However things soon begin to derail as Julia's newfound strength and Alan's chauvinistic mindset clash.
Two years later, his and Julia's daughter - known only as Girl - join them in Toronto. Also arriving to live with them is Alan's mother Chloe, who is not a fan of her daughter-in-law. This puts further strain on their union and, to make matters worse, Alan's religious fervour is escalating to the point of fanaticism, accompanied by bizarre, unpredictable and hostile behaviour. The marriage begins to deteriorate, and Julia realizes that she wants to leave Alan. In 1978, four years after his arrival in Canada, Alan is shot and killed by police in front of his family. For the three women left behind, the tragedy of the killing is a memory which does not fade, leaving each of them haunted by the events of that day. thirsty is a poetic, poignant story of a family's dreams, their struggle, and their eventual undoing.