A boat, a yellow door, and the Graham Quartet are on the alert! Arriving on the shore of Lake Michigan for summer vacation, the Graham Quartet senses that something is not quite right. When a slip of the tongue causes an unexpected reaction, Elsa, Matt, Selena and Tim jump into a mystery. But what is the connection between a cryptic note, a yellow door, and a boat called the Day Maid? When their friend, Lieutenant Ashwood, disappears, the Quartet...