Moonjellies are harmless and bioluminescent, meaning they are able to create light, like fireflies, with chemical reactions in their bodies.  They are made up mostly of water.

Mark spends a busy, noisy day helping out at Gram's seaside hot dog stand. After the last customer is served and the grill is scrubbed to a silvery shine, Mark sails off with Gram for a promised surprise - and finds a nighttime sea full of shimmering moonjellies.

"This beautifully illustrated picture book debut evokes the fullness of a New England childhood through descriptions of a single summer day."

—Publishers Weekly