What can be done to help the oceans remain clean and efficient? Ella and Struan are two rookies determined to become marine biologists. Alex, Ella and Struan take to the sea in Plymouth Sound to examine just how plastic is impacting on underwater life. Then it is off to Malta for a spot of scuba diving. Struan and Ella complete a survey of fish species in the Mediterranean before getting the chance to give some sharks life after death. They extract live eggs from sharks that have been caught by fishermen and then have the amazing experience of releasing two sharks back into the sea.