Riptide takes place immediately after the ending of Dead Island, with the four immune survivors - ex-American football player Logan Carter, rapper Sam B, Hong Kong police officer Xian Mei, and Australian bodyguard Purna - landing on an aircraft carrier after escaping from the prison island. They are immediately taken into custody by the ADF Colonel Sam Hardy and Frank Serpo, a civilian VIP. In the ship's brig, they meet another immune survivor, soldier John Morgan, who claims Serpo stopped the military's evacuation. The player can find excerpts of Morgan's diary throughout the game, showing the military eventually decided to simply firebomb all of Banoi and the entire stricken area.