In this non-stop adventure, Onyx and her fellow Coasties work with the Buffalo Police to save a sinking yacht. Then the Coast Guard must enter the dangerous exclusionary zone of Niagara Falls to rescue a family trappedon a disabled, drifting boat. The current of the Falls is too strong for them to continue, so it's up to Onyx to swim a tow line to the family aboard the boat in trouble. But is all hope lost when Onyx is suddenly pulled under by the might of the river and tangled in the tow line?