《甲板之下第四季》讲述的是：　　Captain Lee, Kate, Ben and Kelley are joined by five new crewmembers as they prepare for a new charter season. The crew welcomes their first charter guests, a social media obsessed darling along with her friends. Kate is tasked with breaking in two new junior stewardesses. With added pressure of being a first time bosun under Captain Lee Kelley has his hands full with his headstrong senior deckhand. Ben and Kate must find their new middle ground as Ben comes to grips with Kateâ€ôs new relationship.