To obtain the Missing: Davis lost and found quest in Dead Island 2, grab it from the missing board at the Serling Hotel in Ocean Avenue during the Boardwalking Dead story quest. Davis was last seen being evacuated by bus to Venice Beach. For this quest, travel to Venice Beach then make your way to the northeastern map transition where all the buses are. Once there, collect the Extra Credit journal from the steps of one of the buses.
You’ll learn that this is the wrong bus stop. The one you’re looking for is at the shoreline near the Pier! Travel to the Lifeguard HQ at the Santa Monica Pier then head north to find a parking lot filled with buses. To enter, slip under the broken fence.
Inside this parking lot you’ll find Davis. Take him down then loot the item he drops. Afterwards, the quest will complete. As a reward, you’ll receive 1,500 XP and an Improvised Hammer.