Kate O'Brien is thirty and has very little to think about except trying to keep her balance as she totters up London's media-land ladder.

Fiona O'Brien is Kate's responsible older sister - with a husband, twin boys, a dog and now ... a life-changing problem.

It's a problem that means Kate going back to Dublin. Pronto. There she finds herself stepping into Fiona's shoes to look after two five-year-old scamps, as well as her widowed father, deluded rapper brother, disapproving brother-in-law and a host of assorted side-kicks. As if that wasn't enough, the ex she thought she'd got over years ago turns up to haunt her.

Will either of the O'Brien sisters survive? And even if they do, can either of them slip back into their old shoes ever again?