Chronicles of Egg: Deadweather and Sunrise by Geoff Rodkey
DEADWEATHER, a sweaty little pirate-infested island, is home to EGG, thirteen years old and prey to a pair of cruel and stupid older siblings. But when Egg's family disappears in a freak accident, he finds himself living on SUNRISE island with the glamorous Pembroke family and their feisty daughter Millicent. Finally, life seems perfect. Until someone tries to throw him off a cliff. Suddenly, Egg is lost in a world of cutthroat pirates and powerful villains. Only Millicent - and a one-handed, possibly deranged cabin boy - can help him as he hurtles into the deadliest adventure of his life . . .