Scaredy Bat and the missing jellyfish
(Book)

"Twelve-year-old Ellie “Scaredy Bat” Spark would give her fangs to prove herself and become a real detective. So when she learns the jellyfish at the lake have vanished, she jumps at the chance to solve the puzzle. But if her fear of boggy water stalls the case, the park will close and her best friend’s dream of going to science camp will be dashed. With only one day to unscramble the riddle, Ellie tries to ignore her dread of swimming and recruits her pals to help search for the missing jellies. Suspecting everything from pollution to sea monsters, the only clue they find is a furry brown rat dogging their heels." --,Provided by publisher.