Philippe Cousteau travels to Curacao and dives along the coral reefs to capture lionfish, an invasive species that’s destroying the sea life in these waters. We visit the Chesapeake Bay to see what’s being done to restore the oyster population. Then Philippe goes to Alaska and sees some areas that are still suffering from the Exxon-Valdez oil spill, which occurred over 25 years ago. Then we explore how the Mississippi River can be used to rebuild the disappearing wetlands in Louisiana.