Watch Flood for Free: How to Stream the Movie Online at 123Movies. . Timely yet terrifying, The Flood predicts the unthinkable. When a raging storm coincides with high seas it unleashes a colossal tidal surge, which travels mercilessly down England's East Coast and into the Thames Estuary. Overwhelming the Barrier, torrents of water pour into the city. The lives of millions of Londoners are at stake.