Sisters Eve and Sam couldn't be more different. Eve is settled in Ireland with her not-quite-husband Liam and their two young children, Max and Lily. Sam has flown the nest to London, where she is a successful journalist and a household name as the champion of working women. But Eve has a happiness Sam envies, and maybe that's what drives her to offer to swap lives with her sister one weekend - partly to give Eve a much-needed holiday, but also partly so she can experience first-hand what it's like to be a wife and mother. Meanwhile, Eve's best friend Anna is a turning point in her relationship with childhood sweetheart Ronan. Ronan is desperate for them to marry, but Anna has a secret that could change everything. Maybe that's what's holding her back from setting the date? Eve can't understand it: she is desperate for Liam to make an honest woman of her. They have two wonderful children together - so why's it so hard for him to take the final step of making her his wife? Maybe the answer lies in Australia, where Liam's work takes him all too often, and where the mysterious Brooke is about to face a dilemma all of her own. One brief weekend that begins as a favour between sisters could have consequences that will change their lives forever...