Growing up on a secluded island of Croatia, sisters Magdalena and Jadranka have learned from their grandfather, the importance of swimming.  The first rule is to make sure you can stay afloat.  In life, they try very hard to do just that, when family secrets find their way back to haunt them after they have grown into young women.  One of the biggest challenges is accepting the fact that they are only half-sisters; Magdalena is the eldest and when she finds out that Jadranka has a different father, she tries to keep this news hidden from her for as long as she can.