The sea-quakes made by Whitebeard cause a tsunami to come upon Marineford. But thanks to Aokiji freezing the water, any real potential damage is prevented. After the first attack, other soldiers join the fray, and the war really begins. While everyone is fighting, Mihawk decides to join the fight and attacks Whitebeard. The episode ends as the giant shockwave from the attack approaches Whitebeard. (thetvdb.com)