Every year, the sandy beach of Haeundae, the most populous district of Busan, becomes a pole of attraction for more than one million visitors from all over the world. Without a doubt, this idyllic seaside resort is the perfect vacation destination; however, the marine geologist, Professor Kim Hwi, has more important reasons to be there. Convinced that a towering tidal wave is heading towards the crammed with tourists Haeundae Beach, Kim desperately urges the authorities to evacuate the city; but, to no avail. Before long, his worst fears become reality, as an unstoppable seismic sea wave is about to hammer the area, threatening to level everything in its path. Is there an escape from the devastating mega-tsunami?