Ottoline at Sea (Ottoline, #3)

Ottoline and Mr. Munroe do everything and go everywhere together. That is, until the day Mr. Munroe mysteriously disappears, leaving a strange clue written in string . . . Armed with her Amateur Roving Collectors' travel pass, Ottoline sets off on a journey over, under and on top of the sea to find her hairy best friend - and bring him back home.