This plot is not realistic because tsunamis do not occur in the open ocean. While tsunamis can be generated by underwater earthquakes, landslides, or volcanic eruptions, they usually travel at high speeds across the open ocean without creating large waves. It is not until they approach shallow water near coastlines that they slow down and can build up into the destructive waves commonly associated with tsunamis. Therefore, it is highly unlikely that a large wave caused by a tsunami would be able to overturn a cruise ship in the open ocean.