Sejal and her brother, Abu, are excited to visit their aunt, who is a marine biologist. During a fun trip to the beach, Abu discovers a small, blue creature washed up on shore. It's a blue dragon! Despite its name, it doesn't breathe fire--but it is fearless, preying on much bigger animals.

Sejal is ready to see the blue dragon in action. With a submarine powered by Imagination Fuel, she plunges into an underseas adventure. She hopes she can learn more about how the small but mighty blue dragon might help her as she deals with her own battle with a class bully.