Roslyn and Liam met nine years ago and have been the perfect couple ever since. Through every up and down, every milestone - from Liam's residency to the publication of Roslyn's debut romance - they've been each other's rocks. Until now. Pulled apart by the untimely death of Roslyn's mom and the undertow of grief, they're now navigating the final wave in their marriage: divorce. Heartbroken and unsure how to tell her family she's called it quits with everyone's favourite son-in-law, Roslyn keeps the impending divorce a secret. But when Roslyn's grandparents ask if Liam can officiate their vow renewal ceremony aboard a Hawaiian cruise during their annual vacation, Roslyn needs to tell the truth or figure out a way to keep her secret. A week trapped at sea with her ex isn't ideal, but neither Roslyn nor Liam want to rock the boat, so they concoct a plan - they'll fake it. After five years of marriage, they can figure out how to pretend for jungle hikes and mai tais, right? But when reality and make-believe start to blur, and old feelings begin to resurface, Roslyn and Liam have to decide whether it's sink or swim for their marriage.