When unbelievably sized hail falls from the sky in the aftermath of a "megatsunami," students on school buses seek shelter from the storm in a superstore called Greenway. From the TV they find in the Media Department, the fourteen kids learn their lives will never be the same again. A chemical leak has occurred and it causes varying side-effects depending on the exposed person's blood type. The kids have to work together despite their differences to survive in Greenway. What can go wrong?