The citizens of London must grapple with one of the greatest environmental crises in British history, and the possible obliteration of the city itself, in Flood, a natural disaster opus from director Tony Mitchell (Supervolcano). In present day England, a colossal storm hits the North Atlantic Ocean just outside of the UK and moves toward the Scotch mainland, laying waste to the town of Wick. Some predict that the crisis will die off; not so Professor Leonard Morrison (Tom Courtenay of Billy Liar), who worked arduously on the Thames River barrier. Morrison presciently foresees the system moving across the Thames barrier, where it will gain added strength from the year's unusually high tide and inundate London with a wall of water. In desperation, Leonard contacts daughter-in-law Sam (Jessalyn Gilsig), Director of Operations for the barrier, and warns her of the impending destruction; Sam's estranged husband (and Leonard's son) Rob (Robert Carlyle), who is employed as an engineer on the Barrier, and Police Commissioner Patricia Nash (Joanne Whalley) also become involved. As the water hits - just as predicted - these officials declare a city-wide state of emergency and must take extreme measures to keep the pending disaster from spiraling out of control and claiming untold numbers of lives .