Princess Amelia is so excited to be starting a new term at the Princess Academy with her best friends Leah, Ruby, Millie, Rachel, and Zoe in Daffodil Room. And what a wonderful surprise—the Princess Academy at Emerald Castle is by the seaside! Princess Amelia saves a baby seal caught up in some netting while the princesses are out swimming one day, but the nasty twins Diamonde and Gruella take all the credit! Will they be found out?

The princesses are off to Emerald Sea World for a school outing—they can't wait to see the wonderful golden seahorse! When Princess Leah notices Diamonde and Gruella behaving oddly, she decides to follow them. Are the nasty twins up to no good again?

Princess Ruby and her friends go out on a boat with the school fairy godmother, Fairy G, to look for Old Grey, the whale whose beautiful song has a magical effect on everyone who hears it. Why is Old Grey late this year? And will the nasty twins Diamonde and Gruella change their ways after hearing her song?

The princesses at Emerald Castle have an art lesson on the beach one day, and Princess Millie can't believe her eyes when she sees a mermaid out at sea! The nasty twins Diamonde and Gruella refuse to believe that mermaids exist, but they are taught a lesson that they will never forget!

When the princesses at Emerald Castle go out on a trip to Seabird Island, Princess Rachel notices a baby dolphin caught in the nets of the fishing boat they are on. Can Princess Rachel save the dolphin? And will Daffodil Room come first in the test on seabirds?

There is a special end of term tradition at Emerald Castle—the princesses get to make wishes using a special wishing shell given to the Princess Academy by a generous sea fairy. If the wish is kind and thoughtful, it will come true! Will Princess Zoe's wish be granted?