The Anderson Twins

It has been three months since Shelby and Daniel solved the Disappearance of Paul Chandler with their new friends Brian and Rachael Goodwin. Now Shelby and Daniel have been asked to go to an island called Mantina with Steve and Clara Austin, who are a couple from church. The island is in the middle of the Pacific Ocean. The Austins are worried about their missionary friend, Jacob Sullivan. Jacob Sullivan went to Mantina six years ago, and it has been six months since Steve and Clara have heard from him. They do not know if he is dead or alive. What will the Anderson twins and Steve and Clara find on the mysterious island of Mantina?