The summer after her first year of college, Isobel "Belly" Conklin is faced with a choice between Jeremiah and Conrad Fisher, brothers she has always loved, when Jeremiah proposes marriage and Conrad confesses that he still loves her.

Belly spends the summer she turns sixteen at the beach just like every other summer of her life, but this time things are very different.

Stella gets a big surprise when her mom plans a trip to visit their family in Mexico! Stella loves marine animals, and she can't wait to see the ocean for the first time, until she arrives and learns that the sea and its life forms are in danger due to pollution. Stella wants to save the ocean, but she knows she can't do it alone. It's going to take a lot of work and help from old and new friends to make a difference, but Stella Díaz never gives...